How to merge PDF files safely
Combining PDF documents is useful when you need to submit several certificates, scans or reports as one file. Before you start, check that every document opens correctly on its own. A damaged or password-protected PDF may not merge successfully in browser-based tools.
1. Put files in the right order
Name files with a number first, such as 01-cover.pdf, 02-form.pdf and 03-receipt.pdf. This makes it easier to confirm the order before downloading the final document. If one file should be first, select it first in the file picker.
2. Keep files manageable
Large scanned PDFs can use a lot of browser memory. If a file is hundreds of megabytes, reduce the scan quality before merging or use desktop software. Keep an untouched copy of the original files until you have opened and checked the merged PDF.
3. Review the downloaded file
Open the result and check the first, middle and last pages. Look for missing pages, upside-down scans and blank sheets. If the document is being submitted to an employer, school or government service, make sure personal information is correct before sharing it.
When not to use a browser merger
Do not use a simple merger to bypass a password, edit a legally signed document or repair a seriously damaged PDF. Those cases need the original source file, authorised access or professional document software.