Each of these can do more than people think and less than they hope. One of them will silently mangle the file.
What is actually possible on each
| Task | Mac Preview | iOS Markup | Google Drive |
|---|---|---|---|
| Annotate and highlight | Yes | Yes | View only |
| Sign | Yes | Yes | No |
| Fill form fields | Yes | Yes | No |
| Reorder or delete pages | Yes | Yes | No |
| Merge documents | Yes, drag between sidebars | No | No |
| Rotate pages | Yes | Yes | No |
| Edit existing text | No | No | Only by converting |
| Add new text | Yes, as an annotation | Yes | No |
The pattern is consistent: both Apple tools do everything except change text that is already there, which is the one thing people most often mean by "edit". Drive does none of it.
Mac Preview is better than its reputation
Preview is a capable PDF tool that most Mac users never open deliberately. Two features in particular are worth knowing.
Page management by drag. Show the thumbnail sidebar in two open documents and you can drag pages between them. That merges, splits and reorders with no tool at all.
A stored signature. Markup → Sign captures a signature from the trackpad or by holding a signed sheet of paper up to the camera. The camera route is genuinely good — it captures real ink with real pressure variation.
The limitation is text. Preview will not let you change a word that is already on the page. You can cover it with a white rectangle and type over it, which looks right and leaves the original text in the file, extractable by anyone.
iOS Markup
Open any PDF in Files, tap the pen icon, and you have annotation, signatures, text boxes and page management. On an iPad with a Pencil it is the best signing experience on any platform.
The trap is where you open it. Tapping an attachment in Mail opens Quick Look, and edits made there sometimes apply to a temporary copy that gets discarded when you leave.
Always save the attachment to Files first, edit there, and share the saved file. If a signature has "not saved" before, that is almost certainly why — the fuller version is in how to sign a PDF on any device.
Google Drive: the one to avoid
Drive previews PDFs and stops there. The tempting option — Open with → Google Docs — is not an editor, it is a converter.
It runs the document through a conversion that discards the PDF layout and rebuilds it as a Docs file. Columns collapse, tables break, images move, and headers land in the middle of the text. On a scanned PDF it runs OCR and produces a wall of unformatted text.
That is occasionally what you want — it is a free way to extract text from a scan. It is never what you want if the document has a layout you care about. Nothing warns you, and the original PDF is untouched, so the damage is recoverable as long as you notice.
The route that works everywhere
For anything the built-in tools cannot do, a browser-based tool works identically on all three platforms and needs no install — which matters most on a locked-down work Mac or an iPhone.
Page operations in particular are the same everywhere: Merge PDF, Split PDF and Rotate PDF all run on the device, so a confidential document does not get uploaded to complete a task the operating system nearly does already.
For genuine text editing, be realistic about the outcome first. What a PDF editor can and cannot do, and why, is covered in why you cannot edit a PDF.
Frequently asked questions
Can I edit a PDF on a Mac without Acrobat?
Preview handles annotation, signing, form filling, page reordering, merging and rotation — everything except changing existing text. Dragging pages between two open thumbnail sidebars merges and splits documents with no other tool.
Can I edit a PDF on an iPhone?
Yes, through Markup in the Files app — annotation, signatures, text boxes and page management, with no app to install. Save the file to Files first; editing inside a Mail preview sometimes changes a temporary copy that gets discarded.
How do I edit a PDF in Google Drive?
You cannot. Drive previews PDFs only. "Open with Google Docs" is a converter, not an editor — it rebuilds the document and usually destroys the layout. Useful for pulling text out of a scan, wrong for anything with a layout you care about.
Why did Google Docs ruin my PDF layout?
Because it converted rather than edited. The conversion discards the PDF layout and reconstructs it as a Docs file, so columns collapse and tables break. Your original PDF is untouched, so nothing is lost as long as you notice before working on the copy.
Can I merge PDFs on a Mac without extra software?
Yes. Open both in Preview, show the thumbnail sidebar in each, and drag pages from one into the other. Then Save As. It is the least-known genuinely useful feature in Preview.
What is the best free way to sign on iPad?
Markup with an Apple Pencil. It captures real handwriting rather than a mouse gesture, which produces a far more natural signature than any desktop method. Preview on a Mac can also capture one through the camera from a signed sheet of paper.