How to Edit a PDF on Mac: What Preview Can Do (and What It Can't)

Every Mac ships with a surprisingly capable PDF editor, and most people have never opened its toolbar. Preview — the app that opens when you double-click a PDF — can fill forms, sign documents, highlight, add text boxes, rearrange pages, and even merge files. What it can't do is change text that's already in the PDF, and that gap is where most "how do I edit a PDF on Mac" searches come from. Here's what Preview handles, and what to use for the rest.

What Preview does well

Open your PDF in Preview and click the pencil-in-a-circle icon (or View > Show Markup Toolbar). From there:

• Fill in forms: click any form field and type. Preview handles most fillable PDFs without fuss.
• Sign documents: click the signature icon in the markup toolbar. You can draw your signature on the trackpad, sign a piece of paper and hold it up to the camera, or sign on your iPhone and have it appear on the Mac. Signatures are saved for reuse.
• Add text boxes: the boxed "A" icon drops a text box anywhere — useful for annotating or filling in forms that aren't properly fillable.
• Highlight and note: the highlighter dropdown covers highlighting, underlining, and strikethrough; sticky notes live under the notepad icon.
• Rearrange, rotate, delete pages: open the thumbnail sidebar (View > Thumbnails) and drag pages around, or select one and press delete.
• Merge PDFs: drag one PDF's thumbnail into another's sidebar. Genuinely that easy.
• Redact (macOS Ventura and later): Tools > Redact actually removes content, not just covers it.

What Preview can't do

Preview cannot edit the text that's already printed in the PDF. There's no way to fix a typo in a contract, change a date on a letter, or update a price on a menu. It also can't whiteout existing content (outside redaction), swap images, or reliably edit complex forms. For years the standard advice was "buy Acrobat," which is a lot of subscription for fixing one typo.

The free route: our browser-based PDF editor handles exactly this gap — click on existing text and retype it, whiteout what shouldn't be there, add images, and download the result. It runs entirely in Safari (or any browser) on your Mac, and the file is processed locally on your machine rather than uploaded to a server. If you're curious how that works, we've written about why "no upload" matters.

Other common PDF jobs on a Mac

• Make a PDF smaller: Preview's File > Export > Quartz Filter > Reduce File Size works but is brutal with image quality — photos come out muddy. Our compressor gives you a quality dial instead.
• PDF to Word: there's no built-in way. Use our PDF to Word converter, then open the result in Word or Pages.
• Password-protect: File > Export, tick Encrypt. Or use our encrypt tool if you want finer control over permissions.

The short version

Reach for Preview first — for forms, signatures, highlights, and page shuffling, it's excellent and already installed. The moment you need to change words that are already on the page, switch to the browser editor. Between the two, there's very little left that needs a paid app.