The contract, the appendix, and the signed acceptance arrived as three separate files, but accounting or a portal wants a single document. Or you're assembling a visa packet from certificates that came in piecemeal. Merging PDFs handles this in a minute — but you have to watch the page order yourself, or the documents end up shuffled.
How to merge PDFs, step by step
1. Open merge-pdf and upload all the files you need. 2. Arrange them in the right order by dragging, not by filename. This is the key step. 3. Check the order in the thumbnails: the first file should come first, the last should come last. 4. Run the merge and download the finished document. 5. Open the result and scroll through the seams between files — that's where a wrong order shows up first.
A real-world example
A freelancer had to submit one PDF invoice packet but had the invoice, the timesheet, and a receipt as three scans. In **merge-pdf** they dragged them into invoice → timesheet → receipt order, glanced at the thumbnails to confirm, and downloaded a single clean file. The client's portal accepted it without complaint.
What can go wrong
- **The files merged in the wrong order.** The most common cause is assuming the tool sorts them for you. Always arrange them by hand and check the preview.
- **Extra pages slipped in.** If one file had a blank sheet or a draft, remove it first with **remove-pages**, or fix the order with **organize-pdf**.
- **The final file is too heavy.** Several scans add up. Compress the result with **compress-pdf**.
- **Sideways pages.** If one source was scanned rotated, it stays that way after merging — fix the orientation before you combine.
A common mistake
The common mistake is trusting filenames to set the order. "Document (1)" and "Document (10)" sort in surprising ways, and a packet can come out with the signature page buried in the middle. Drag the files into place and verify with the thumbnails before merging.
What to check before sending
- The document order matches what the recipient expects.
- No pages were lost or duplicated at the seams.
- The final file fits the size limit.
- Every page is oriented correctly.
To combine a set of documents into one file, upload the parts to **merge-pdf** and arrange them in order. **organize-pdf** helps tidy the pages inside, and **compress-pdf** trims the size of the finished document.