An application wants “all supporting documents in a single PDF”. You have an ID scan, a certificate, a bank letter and a two-page form, all separate files. Merging them takes less than a minute with the right tool. What's worth a little more thought is the order, and the handful of things that don't survive a merge.
Ways to merge PDFs
In your browser, on any device
Our Merge PDF tool combines files inside your browser: nothing is uploaded, which matters when the documents are IDs and contracts. Add the files, arrange them, and download one PDF. Each file shows a number for its position in the final document. We did this deliberately: in Arabic the list reads right to left and in English left to right, and “which one is first?” shouldn't depend on which language the page is in.
Merge PDF Put the files in the order you want, then merge them into one document.
On a Mac: Preview
Open the first PDF in Preview and turn on View → Thumbnails. Drag the other PDF files from Finder into the thumbnail sidebar, dropping each where it should go, then use File → Export as PDF to save the combined file under a new name. Exporting rather than saving leaves your first file untouched.
On an iPhone or iPad: the Files app
In Files, tap Select, choose the PDFs (and photos, if you like), tap the More button and choose Create PDF. The order follows how the files are sorted in the folder, so rename them first if the order matters, for example “1 ID”, “2 Certificate”.
On Windows
Windows has no built-in way to combine PDFs. “Microsoft Print to PDF” can only print one document at a time. Use a browser-based tool, or Adobe Acrobat's Combine Files feature if you have a paid licence.
Getting the order right
- Follow the list you were given. If the application lists required documents, merge them in that order. The person reviewing it will be working down the same list.
- Number your files before you start. Renaming them “01”, “02”, “03” makes every tool and every file browser show them in the right order.
- Inserting a page in the middle of a document? Split the document at that point, then merge the pieces with the new page in between.
- Watch for rotated pages. A page scanned sideways stays sideways after merging. Fix the rotation in the source file first.
Split PDF Pull out just the pages you need, or separate every page into its own file.
What carries over, and what doesn't
Merging copies pages as they are, so most things come through intact: text stays selectable and searchable, images keep their original resolution, and each page keeps its own size, so an A4 page and a Letter page can sit side by side. A few things are different:
| Item | After merging | What to do |
|---|---|---|
| Text, images, page size | Kept exactly | Nothing |
| Bookmarks (the side-panel table of contents) | Usually lost | Recreate them afterwards if the combined document needs them |
| Fillable form fields | May stop being fillable | Fill in and save the form before merging |
| Digital signatures | No longer valid | Send signed documents as separate files, or merge first and sign the result |
| Password protection | The file can't be read | Open it with the password and save an unprotected copy first |
A digital signature certifies one exact file. A merged PDF is a new file, so the signature no longer matches what it signed. Many PDF readers will then show a warning. If an organisation requires a signed document, don't fold it into a merged bundle unless they've said that's acceptable.
Keeping the merged file a sensible size
A merged PDF is roughly the sum of its parts. Three text documents of 100 KB each make about 300 KB, and three scans of 2 MB each make about 6 MB. If you're heading for an upload portal, add up the sizes before merging. If the total is too big, compress the scanned files first, or compress the merged result. Our guide to reducing PDF file size explains which approach suits which kind of file.
If some of your documents are photos rather than PDFs, convert them into PDF pages first and shrink them on the way. There's no reason for a photographed receipt to weigh 4 MB.
JPG to PDF Collect several images into one tidy PDF document.
A final check
- Scroll through the whole merged file once. Is every page there, in order, and the right way up?
- Give it a clear name, such as “Application-documents-Ahmed.pdf”, not “merged(3).pdf”.
- Keep the individual originals. If a reviewer asks for one document on its own, you'll want it.