PDF Combiner
Three scans, a contract from email and a photo of a receipt — and the upload form takes one file.
Merging looks trivial until you do it with six documents in a hurry: in the wrong order, one of them sideways, one of them locked. The difference between a minute and half an evening is whether the tool takes the whole stack at once or one file at a time.
Merge the whole stack in one pass
PDF Combiner puts the entire job on one screen — everything goes in, you set the order, one document comes out. The same screen works on iPhone, iPad and Mac.
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Open Merge PDF and choose your files
The picker offers PDF, Scanner and Photos. Take the whole stack in one selection — tap the files you want or use Select All — instead of adding documents one at a time.
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Set the order by dragging
Files arrive in whatever order the picker hands them over, which is rarely the order you tapped them in. Hold an item and drag it where it belongs; swipe left to drop one that shouldn’t be there. Append + takes more files at any point before you export.
- 3
Deal with anything locked
A password-protected PDF is flagged in the list with a lock. Tap it, enter the password once, and it joins the rest — no detour through unlocking and re-saving a copy somewhere else first.
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Combine documents
One export for the whole stack. The result screen lets you rename the file before it goes anywhere, then saves or shares it — and if the merged document still needs work, it hands straight over to the next tool.
One detail worth knowing in advance: Scanner sits inside that same picker. The one signed sheet that only exists on paper gets scanned directly into the stack, rather than becoming a separate trip through the camera, Photos and Files.
All of it runs on the device. Merging works in airplane mode — which is the part that matters when the stack is a lease, a medical result or a passport scan.
Mixed page sizes: even them out before you export
A merged PDF keeps the page size of every source file. An A4 contract, then a Letter scan, then a page made from a phone photo, and the finished document changes width three times — margins jump around in print and the zoom level fights you on screen.
The Pages Width Alignment toggle sits at the top of the merge screen and makes every page the same width on the way out. Worth switching on whenever the result is going to a printer, into another merge later, or to someone who’ll read it on a phone.
What the built-in tools do
Both Apple platforms merge PDFs, and for two files they’re the shortest route.
On iPhone and iPad, Preview has done this since iOS 26. Open the first PDF and tap the page count to bring up the thumbnails — if the count isn’t showing, pinch two fingers together or apart on the page. Then touch and hold a thumbnail and choose Insert from File. Insert Blank Page and Scan Pages are in the same menu, and touch-and-hold-then-drag reorders pages.
On Mac, open the PDFs you want to join, choose View → Thumbnails in each, and drag thumbnails from one sidebar into the other — Command-click to pick up pages that aren’t next to each other. To append an entire document, drag its icon from the Finder onto the sidebar.
The ceiling is the same on both: Preview is built around one open document. Every extra file is another touch-and-hold, another Insert from File, another trip through the picker — and no place to see the whole stack at once. That’s fine twice. At six you’ve lost track of what went in where.
A merged file isn’t a smaller file
Nothing is re-encoded during a merge, so nothing loses quality — pages cross over exactly as they were. Nothing shrinks either. A 914 KB portfolio and a 1.35 MB recipe book came out of our own merge as a single 1.7 MB document: slightly under the sum, because the two files shared fonts, but nowhere near smaller.
Mail servers usually stop somewhere around 20–25 MB. If the merged file bounces, that’s a compression problem — and it’s about what’s inside the pages, not about the merge.
Photos and scans in the same document
A photo of a receipt can end up in the same document as a contract from email — but a photo becoming a page involves decisions a PDF doesn’t: what size that page is, whether the image fills it, and how heavy the result gets. That’s a topic of its own — see combining PDFs and JPGs into one file.
After the merge
A stack that came off a scanner almost always needs one pass of cleanup: the blank backs a duplex scanner adds to every single-sided sheet, a file that went in sideways, a cover page that belongs at the front. Doing it after the merge means one document to fix instead of five, and deleting, rotating and rearranging pages is covered separately — as is the reverse trip, splitting a PDF back into separate files.
More walkthroughs like this one are in the PDF Combiner guides.