iPhone doesn't have a built-in PDF merger in the way Mac does with Preview, but there are two practical routes that don't require installing a dedicated app โ one through the Files app and one through a browser.
The Files App Method
iOS 16 and later added PDF merging directly into the Files app. Open Files, navigate to the folder containing your PDFs. Long-press on one file to enter selection mode, then tap the other PDFs you want to include. Once all the files are selected, tap the three-dot menu in the bottom-right corner and look for Create PDF or Merge โ the exact label varies by iOS version. The merged PDF saves to the same folder.
The merge order follows the selection order, so tap the files in the sequence you want them to appear in the final document. If you selected them in the wrong order, it's faster to deselect all and reselect in the correct sequence than to try to reorder after the fact.
This method isn't available on all iOS versions and the option doesn't always appear consistently โ Apple's Files app PDF features have been somewhat inconsistent across iOS releases. If you don't see a merge option after selecting multiple PDFs, the browser method works on any iOS version.
Browser Method: Works on Any iPhone
Open Safari, go to WukongPDF, and use the Merge PDF tool. Tap the upload button and select your PDFs from Files โ you can select multiple files at once by tapping Select in the Files picker and choosing each one. After uploading, drag to reorder if needed, then tap merge and download the result. The merged PDF downloads to your iPhone and appears in the Files app under Downloads.
This works on iOS 14 and later and doesn't require any app installation. Safari handles the upload and download exactly as it would on a desktop browser, so the full merge functionality is available including reordering pages before combining.
After Merging: Sharing the Combined PDF
Once the merged PDF is in Files, tap and hold it to bring up the share sheet. From there you can send it via Mail, Messages, AirDrop, or save it to iCloud Drive for access across your devices. If the merged file is large โ several PDFs combined can add up quickly โ consider running it through a compression tool before sending, particularly if it's going out by email where attachment size limits apply.