You’ve got a PDF in your inbox and you’re standing in a queue with only your iPhone. Maybe it’s too big to send back, maybe it needs your signature, maybe two files need to become one. The good news: you don’t need to install anything from the App Store. This guide covers what an iPhone or iPad can do with PDFs on its own, and how to handle the rest — compress, merge, sign, convert — right in Safari.
What an iPhone can do with PDFs on its own
iOS has quietly capable, if scattered, PDF features — worth knowing before you reach for anything else:
- Save anything as a PDF — open the Share sheet, tap Print, then pinch outward on the preview to turn it into a PDF you can Save to Files.
- Sign and annotate — open a PDF in Files or Mail and tap the Markup (pen) icon to add a signature, initials, or notes.
- Store and read — the Files app and Apple Books both keep PDFs neatly.
What iOS can’t do natively is compress a PDF, merge several into one, convert a PDF to Word or Excel, or run OCR on a scan. That’s the gap Ream fills — without an app.
How to compress, merge or convert a PDF on iPhone
- Open ream.pro in Safari and tap the tool you need — for example Compress PDF.
- Add your PDF from Files, iCloud Drive, or wherever it lives, using the file picker.
- Run the tool and download — tap Save to Files (or long-press to share it onward).
No account, no App Store trip, no watermark. Many tools — merging, signing, reordering, images to PDF — run right inside Safari on your device, so the file never leaves your iPhone. Here’s exactly what runs where.
On-device vs. private sandbox — and why it matters on a phone
The tasks that only rearrange a PDF — merge, organize, sign, images to PDF — run in Safari itself, so your file stays on the phone. The heavier ones that need real processing power — compress, convert, OCR — run on Ream’s server in a network-isolated sandbox that deletes your file immediately. Either way there’s no App Store permission, no photo-library access, and nothing kept.
Emailing from your phone? If a PDF is too large to send, run it through Compress PDF first — see how to shrink a PDF for email. Need a signature on the go? Signing a PDF works with your finger on the screen.
Is it private, and is it free?
Yes to both. There’s nothing to install and nothing to pay for — no account, no watermark. The browser tools keep your file on your iPhone; the sandbox tools delete it straight after. It’s the same set of tools you’d use on a Mac, Windows PC, or Android phone — because it all runs in the browser.
Frequently asked questions
How do I compress a PDF on my iPhone? Open Compress PDF in Safari, add the file, compress, and Save to Files — no app needed. iOS has no built-in PDF compressor.
How do I save something as a PDF on iPhone? Use the Share sheet → Print, then pinch outward on the preview and tap Save to Files. To turn photos into one PDF, use Images to PDF.
Can I sign a PDF on my iPhone? Yes — open it in Files and use Markup, or use Sign PDF to draw your signature with your finger.
How do I merge two PDFs on iPhone? Open Merge PDF in Safari, add both files, arrange them, and download the combined PDF.
Do I need to download an app? No — everything runs in Safari on iPhone and iPad. There’s nothing in the App Store to install.
Are my files uploaded when I use it on my phone? The light tools run on your device; only the heavy ones (compress, convert, OCR) use Ream’s isolated sandbox, which deletes your file immediately.
Is it free? Yes — free, no sign-up, and no watermark.
Your iPhone can do more with PDFs than it lets on — and for everything it can’t, Safari and Ream cover the rest without an app. Start with Compress PDF, Merge PDF, or Sign PDF, and the same tools follow you to your Mac, PC, or Android.
