Three checks before merging a PDF

Keep a copy of each original. When merging PDFs, the input file order determines the order of pages in the output. Numbered file names can help you check the order of covers, main sections and appendices.

Password-protected documents and digitally signed files require special care. Copying pages does not guarantee preservation of a digital signature. Keep the signed original and check whether the recipient accepts an edited copy.

After downloading, inspect the first page, the boundaries between source documents and the last page. Compare the total page count with the sum of the originals. Cropping changes the visible area; it is not a way to remove confidential content.