Merging is simple when the files are already clean. The mistakes usually happen before processing: an attachment is omitted, files are sorted alphabetically instead of logically, or rotated scans are left sideways.

Use the same checklist on a phone or computer; only the file picker changes.

Prepare the source files

Rename files with a numeric prefix such as 01-cover, 02-contract and 03-appendix. Remove passwords you are authorized to remove, and rotate any sideways pages before combining.

  • Keep an untouched copy of every source file.
  • Confirm each file opens and has the expected page count.
  • Avoid merging different document versions by accident.

Merge and reorder visually

Open the Merge PDF tool, select all files, and use the preview grid to drag them into the final sequence. On a phone, tap the add-file control again if the operating system picker only allowed one location at a time. Run the merge only after the visible order is correct.

Verify the combined PDF

Download and check the page count, transitions between documents, orientation, links and form fields. Mixed A4 and Letter pages are valid, but they can look uneven in a continuous viewer or print unexpectedly. Resize only when a consistent sheet size is genuinely required.