How to merge several PDFs into a single file

Why merge PDFs

Sending a single organized file is more professional and safer than sending five loose attachments. The recipient opens one document, in the order you set, with no risk of losing a part. Sign-up portals, job applications, expense reports and submissions to government agencies often accept only one file per field anyway.

Prepare the files first

A little organization saves rework:

• Gather all the documents in the same folder.
• Rename the files with numbers in front (01, 02, 03), in the order they should appear.
• If any file is a photo or an image scan, convert it to PDF first with Image to PDF.
• If any PDF is password-protected, remove the protection with Unlock PDF, entering the current password.

How to merge PDFs step by step

In the Merge PDF tool:

1. Select the files or drag them onto the tool area. You can combine up to 20 files at once, up to 60 MB each.
2. Check the order using the thumbnails and fix anything out of place.
3. Click merge and wait for processing.
4. Download the combined PDF and open the file to check that all pages are there and in the right order.

If the page order is not what you wanted

After merging, you can rearrange the pages of the final document with Reorder Pages. You see thumbnails of every page, drag each one into place and can remove the ones you do not need. This is useful when one of the original files had pages out of sequence.

The final file is too large

Adding PDFs together also adds up their sizes. If the result is over the limit of the email service or portal you are sending to, use Compress PDF after merging. Compressing once, on the final file, is simpler than compressing each document separately.

For reference, many email services limit attachments to 20 or 25 MB, and many government portals accept only 2 to 10 MB per file. Check the recipient’s limit before you start.

Good practices

Before sending the combined document to someone:

• Open the whole file and check every page, especially signature pages and attachments.
• Give the file a clear name, such as "contract-company-x-2026.pdf", instead of generic names.
• Keep the original files until you are sure the submission was accepted.
• If the document contains personal data, consider protecting it with a password using Protect PDF.

Frequently asked questions