A contract arrives as an email attachment and needs a signature before the end of the day. A form needs filling. A twelve-page report needs three pages removed and the rest put in a sensible order. Every one of those jobs can be finished on an iPhone in a couple of minutes, and none of them require installing anything, because iOS has shipped with a capable set of PDF tools for years. Most people simply never find them.
This guide covers what those built-in tools actually do, the one significant thing they cannot, and the fastest route through each common task on both iPhone and iPad.
First, decide which kind of editing you need
Almost all confusion about editing PDFs on iOS comes from two different jobs sharing one word. Sorting out which you need takes seconds and saves you hunting for a feature that does not exist.
Annotating means adding things on top of the page: a signature, a highlight, a comment, a tick in a box, text typed into a blank field, a redaction over a private detail. It also covers rearranging the document itself, such as deleting, rotating, or reordering pages. All of this is built into iOS and free.
True text editing means changing words that are already part of the document, so that a typo in a printed sentence is corrected and the surrounding lines reflow around it. iOS does not do this, and the reason is structural rather than an oversight. A PDF records text as fixed content pinned to exact coordinates, not as a flowing document, so altering one word means recomputing the layout around it. That capability belongs to dedicated editors.
The short version: if you need to sign, fill, highlight, comment, redact, or reorganise pages, everything you need is already on your phone. If you need to rewrite the document's original sentences, you need an app.
Method 1: Markup, the editor you already own
Markup is Apple's annotation layer, and it appears in every app that displays a document: Files, Mail, Photos, Books, Safari, and Messages. Learning it once means you can edit a PDF from wherever it happens to arrive.
Opening Markup
Open the PDF in the Files app and look for the Markup button, drawn as a pen tip. On an emailed attachment, tap the attachment to open it and the same button appears. If a document opens in a preview that has no visible tools, use the share button and choose Markup from the list of actions.
What each tool is for
The toolbar looks minimal but covers a great deal:
- Pen, highlighter, and pencil: Freehand marks. The highlighter is the right choice for review comments because it sits behind the text rather than obscuring it.
- Eraser: Removes your own annotations only. It never damages the underlying document, which makes experimenting safe.
- Lasso: Selects a mark you have already made so you can move or resize it. This is the tool most people miss, and it turns a misplaced annotation from a redo into a drag.
- Text box: Types onto the page. Essential for filling forms that have no interactive fields, which describes most forms that arrive as scans.
- Signature: Stores a reusable signature, covered in detail below.
- Shapes: Lines, arrows, rectangles, and speech bubbles for pointing at a specific detail.
- Colour and thickness: Choose a colour that contrasts with the document so your marks are obviously additions and not part of the original.
A practical habit worth adopting: work on a duplicate. Long-press the file in Files and choose Duplicate before you start annotating. Markup writes into the file you opened, and keeping a clean original costs one tap.
Method 2: Signing a PDF and filling in forms
Signing is the single most common reason people search for how to edit a PDF on an iPhone, and it is genuinely a thirty-second job.
Open the document, tap Markup, then the plus button, and choose Signature. Draw your signature with a finger or an Apple Pencil. A fingertip signature looks better than most people expect, particularly if you draw large and let iOS scale it down. The signature is saved, so every future document takes a single tap. Drag it into position over the signature line and use the corner handles to size it.
For the rest of the form, the approach depends on how the document was made. A PDF built with proper interactive fields will let you tap straight into each box and type, and recent versions of iOS can even suggest your saved contact details for common fields such as name and address. A scanned form has no fields at all, so use the text box tool instead: place one, type, then size it to sit on the line. Duplicating a text box you have already sized is faster than creating each one from scratch.
When you are done, save and share. Sending the annotated copy rather than the original is the step people forget, and it results in an unsigned document arriving at the other end.
Method 3: Reordering, rotating, deleting, and inserting pages
Page management is a real editing capability, and it lives in the Files app rather than in Markup, which is why it goes unnoticed.
Open the PDF in Files and show the page thumbnails. Dragging a thumbnail moves that page in the document. Pressing and holding one opens a menu with the operations you would expect from desktop software: rotate the page, insert a blank one, insert a page from another file, scan a new page in with the camera, or delete the page entirely. Changes are written back into the document.
This covers a surprising share of real-world requests. Removing the two pages of legal boilerplate before circulating a report, turning a sideways scan the right way up, or slotting a signed page back into the middle of a contract are all handled here with no extra software.
Method 4: Combining files and creating new PDFs
Merging is built in as well. In the Files app, select the documents or images you want to join, then choose Create PDF from the share or overflow menu. The order you select them in becomes the order of the pages, so select deliberately rather than tapping at random and reordering afterwards.
There is also a useful trick for turning almost anything into a PDF: open the item, choose Print from the share sheet, and save the print preview as a PDF instead of sending it to a printer. Because it works from the print pipeline, it captures web pages, notes, and app content that offer no PDF export of their own.
Method 5: Scanning paper into a searchable PDF
The Notes app contains a document scanner that is considerably better than photographing a page. Create a note, tap the attachment button, and choose Scan Documents. Hold the phone over the page and it detects the edges, corrects the perspective so the page looks square rather than trapezoidal, and cleans up the contrast. Multiple pages collect into a single PDF.
iOS also recognises the text inside those scans, so you can select words and search the document rather than treating it as a flat image. Recognition is strong on clean printed pages and less reliable on faint print, unusual layouts, or handwriting, so check anything important rather than assuming a perfect reading.
Light matters more than megapixels
Scan quality is decided almost entirely by lighting. Even, indirect light with no shadow from your own hand produces a cleaner and more accurately recognised page than any camera setting. If the scan looks grey and mottled, move rather than adjust.
Method 6: When you genuinely need a third-party editor
Four jobs sit outside what iOS includes, and all four are worth an app if they come up regularly: rewriting the document's original text, optical character recognition across a large batch of scans, encrypting a file with a password, and true redaction that removes the underlying content rather than drawing a black box over it.
That last distinction is the one that causes real damage. Drawing a filled rectangle over a private detail hides it visually while leaving the text intact underneath, where it can be selected, copied, or recovered. Proper redaction deletes the content. If you are obscuring anything genuinely sensitive, use a tool with a dedicated redaction feature and verify the result by trying to select the text afterwards.
Our roundup of the best PDF editor apps for iPhone and iPad compares the leading options, including which capabilities are free and which sit behind a subscription.
Method 7: Converting instead of editing
A good number of tasks framed as editing are really conversions, and reaching for a converter is quicker than fighting an editor.
When you need individual pages as pictures, for a slide, a social post, or a message, convert the PDF to JPG images and use the pages you want. When you have photographs or screenshots to send as one tidy document rather than a dozen attachments, our JPG to PDF converter combines them in order. And when a PDF is really a presentation you want to work with as slides, our image to PPT converter builds an editable deck from the exported pages.
These run in the browser on your own device, so they work in Safari on an iPhone with nothing to install and no upload of your documents to a server.
Reducing PDF file size on an iPhone
iOS has no built-in compressor, which is a genuine gap. Three approaches work in practice.
Address the cause first: scanned documents are large because every page is a full photograph, so scanning at a sensible size beats compressing afterwards. Second, remove what you do not need, since deleting pages is the simplest size reduction available and it is free. Third, if you build PDFs from images regularly, shrink the pictures before combining them rather than after. When none of that is enough, a third-party editor with a compression feature is the remaining option.
Password protection and privacy
Encrypting a PDF with a password is not something the built-in tools can do. If the aim is simply to keep a document private on your own device, a locked note or a secured cloud folder is usually more practical than encrypting the file itself. If the file must stay protected after you send it, you need an editor that supports encryption, and the recipient needs the password through a separate channel rather than in the same email.
One habit is worth building regardless: before sharing any document you have annotated, open the version you are about to send and check it. Confirm the signature is present, the redactions cover what they should, and you are sending the edited copy rather than the pristine original.
Troubleshooting
The Markup button is missing
You are probably in an app that only previews documents. Open the file from the Files app instead, or use the share button and pick Markup from the list of actions. Files is the most capable PDF surface on iOS, so it is the right default for any real editing.
My annotations disappeared
Usually the edits were never committed, because the document was closed without saving, or they were saved into a temporary preview copy of an attachment rather than a stored file. Save attachments to Files first, then annotate, and the changes have somewhere permanent to live.
I cannot select any text in the document
The PDF is an image rather than text, which is normal for anything scanned or photographed. Selectable text requires character recognition. Rescanning through the Notes app will often produce a searchable result; a large batch needs an app with proper OCR.
The file opens sideways
Rotation is stored in the document, so rotating your phone will not fix it. Open the page thumbnails in Files, press and hold the page, and rotate it there. The correction is saved into the file, so it opens correctly for everyone.
A form will not let me type
The document has no interactive fields, which means it is almost certainly a scan. Use the Markup text box tool to place your own text on the page instead of looking for a field that was never there.
Frequently Asked Questions
Can I edit a PDF on iPhone without downloading an app?
Yes, for most everyday tasks. The Markup tools built into the Files, Photos, Mail, and Books apps let you write, highlight, add text boxes, insert a signature, and draw shapes. The Files app also lets you rotate, delete, reorder, and insert pages. What the built-in tools cannot do is rewrite the original text of a PDF, which requires a third-party editor.
Why can I not edit the existing text in my PDF on iOS?
A PDF stores text as fixed, positioned content rather than as an editable flowing document. Changing a word means recalculating the layout around it, which only dedicated editors with a text-reflow engine can do. Apple Markup is an annotation layer, so it adds content on top of the page instead of altering what is underneath.
How do I sign a PDF on my iPhone?
Open the PDF, tap the Markup button, then the plus button, and choose Signature. Draw your signature once with a finger or Apple Pencil and it is saved for reuse. Drag it into position and resize it with the corner handles, then save the file.
How do I delete or reorder pages in a PDF on iPad?
Open the PDF in the Files app and show the page thumbnails. Press and hold any thumbnail to reach options including rotate, insert, and delete, and drag a thumbnail to a new position to reorder it. Changes are written straight back into the file.
Can I combine several PDFs into one on iOS?
Yes. In the Files app, select the documents you want, then choose Create PDF from the share or overflow menu to merge them into a single file. Selection order determines the order of the pages, so select them in the sequence you want.
How do I make a scanned PDF searchable on iPhone?
Scan the pages with the Notes app document scanner, which produces a sharp, deskewed PDF. iOS recognises text in those scans through Live Text, so you can select and search words in the document. Very poor originals, faint print, or unusual handwriting will still recognise imperfectly.
How do I reduce the size of a PDF on an iPhone?
iOS has no built-in PDF compressor. The practical options are to shrink the source images before creating the PDF, remove pages you do not need, or use a third-party editor with a compression feature. Scanned documents are usually the largest offenders because every page is a full photograph.
Can I password protect a PDF on iOS?
Not with the built-in tools alone. Adding password encryption to a PDF requires a third-party editor that supports it. For simply keeping a document private on your own device, storing it in a locked note or a secured cloud folder is usually the more practical route.
Final thoughts
The honest summary of editing PDFs on iOS is that the built-in tools cover far more than their reputation suggests. Signing, filling, highlighting, commenting, merging, scanning, and reorganising pages are all free and already installed. The single genuine limitation is rewriting the document's original text, and that is a consequence of how the format works rather than something Apple forgot.
So work outward from what you have. Reach for Markup and the Files app first, use a converter when the task is really a change of format, and buy an app only for the specific jobs that need one: text editing, bulk character recognition, encryption, or true redaction. Most days, your iPhone is already enough.