How to highlight and annotate a PDF on your iPhone or iPad
Highlight, underline and add notes to a PDF on your iPhone or iPad, then read it in Night or Sepia mode. Included in myPDF, no account needed.
You have a 40-page reading for class, a contract to review or a report your manager wants comments on. Reading it is fine on a phone. Marking it up is where it gets fiddly: you want to highlight the lines that matter, leave a note next to a clause, and find all of it again tomorrow.
This guide shows the quick built-in option first, then how to highlight and annotate a PDF in myPDF. We make myPDF, so it’s the tool we know best. Highlighting, underlining, notes and drawing work in myPDF without Pro.
The built-in option: Markup
Your iPhone can already draw on a PDF. Open the file in the Files app, tap the pen icon to turn on Markup, and use the pen or the highlighter pen to draw over the page. Tap Done to save.
That works for a quick signature-style scribble or circling one number. It’s a drawing on top of the page, though, not a highlight on the text. Your strokes don’t follow the lines, they’re hard to keep neat on a small screen, and there is no list of notes you can jump back to. For a long reading or a contract you’ll come back to, selecting the text itself works better.
How to highlight a PDF on iPhone, step by step
- Open the PDF in myPDF. If it came by email or from a website, save it to Files first, then open it from there.
- Tap Annotate in the bar at the bottom of the screen.
- Find the passage. Scroll, or use Search at the top of the document if you know a word from the line you want.
- Select the text. Press and hold on the first word, then drag the handles to the end of the passage.
- Tap Highlight.
- Keep going. Select the next passage and repeat. The highlight sits on the text itself, so it stays straight and readable.
On an iPad the steps are the same, and the bigger screen makes long selections easier.
Underline, notes and drawing
Highlighting isn’t the only tool:
- Underline works the same way as Highlight. Some people use highlight for key facts and underline for things to check later. Pick a system and stick to it.
- Notes attach a short comment to the selected text. Use it for questions (“does this apply to us?”) or a reminder of what to reply.
- Strike out marks text that should go. Drawing with your finger or Apple Pencil covers anything that isn’t text: circle a figure in a chart or add an arrow.
- Stamps mark a page at a glance, for example when a document is approved or still a draft.
If you send a marked-up copy to someone else, you can also add a text watermark to every page, such as “DRAFT” or “For review”, and check it in the live preview before you apply it. Watermarks are part of myPDF Pro.
Read it more comfortably
Long PDFs are tiring on a bright screen. myPDF has two reading modes: Night for the evening and Sepia for a softer, paper-like page. The screen stays on while you read, and the file reopens on the last page. Switch to one before a long reading session, then highlight as usual.
Tips for study and review
- Highlight less than you think. If half the page is yellow, nothing stands out. One or two lines per page is usually enough.
- Write the note while you remember why. A highlight tells you a line mattered. A note tells you why.
- Keep an untouched copy. For a contract or a form you’ll sign, duplicate the file in Files before you mark it up, so you still have the clean version.
- Annotate first, share after. Finish your notes, then use Share to send the file by mail or save it to Files.
What this can’t do
Annotations are added on top of the PDF. They don’t change the original text. If you need to fix a typo or a date in the document itself, that’s Edit text, which is part of myPDF Pro. It works on PDFs with real text; scanned pages can’t be edited. For bigger rewrites, export the PDF to Word (also Pro), edit it there and make a new PDF.
A highlight also doesn’t hide anything. If you want to remove an account number or a name before you send a file, that’s redaction, which is a different tool. Our guide on how to redact a PDF on your iPhone covers it.
These steps are written for iPhone and iPad. myPDF is on Google Play too, but the Android feature set may differ, so check there before you count on it.
Quick recap
For a quick circle or scribble, Markup in the Files app is enough. For real reading and review, open the PDF in myPDF, select the text and tap Highlight, Underline or add a note. Switch to Night or Sepia for long sessions, and keep a clean copy of anything you’ll sign.