How to merge PDF files on an iPhone
Why the order matters more than you expect
Merging rebuilds the document from scratch. The page content survives, but structural extras often do not: bookmarks from the second file are usually dropped, and internal links that pointed to a page in the old numbering can end up pointing at the wrong page.
After combining anything important — a contract, a submission, a report — scroll the whole document once. It takes a minute and catches the two mistakes that actually happen: pages in the wrong order, and a page accidentally included twice.
What about merging on a Mac?
Preview can do it: open one PDF, show thumbnails in the sidebar, then drag the second PDF's thumbnails in. That works well but it is a desktop workflow — there is no equivalent gesture on iOS, which is why the question comes up so often.
File size after merging
The result is roughly the sum of the parts. If both files are scans, the merged document can be large enough that email rejects it. Compressing afterwards re-encodes the images and is lossy, so compress a copy rather than your only version.
Step by step
- Put both files somewhere the app can reach
Files, iCloud Drive or the app's own storage. Merging works on files, not on links. - Open the merge or organize view
Select every document you want combined, in the order you want them. - Drag pages into the final order
Do this before exporting. Reordering afterwards means merging again. - Export as a new document
Keep the originals. A merge is not reversible once you delete the sources.
Our iOS app for exactly this. Runs on your device — no account, no tracking.
Free, no sign-up, nothing leaves your device.