The best pdf merger on Windows 11 for combining PDF files?

This is a truly best method of the PDF merger for Windows 11. There is a Firefox browser extension called "PDF Merger and Compressor" that works completely offline—it processes everything locally in your browser without uploading files to any server.

You can do that by :

1. Open Firefox browser on Windows 11

2. Go to the Firefox Firefox plugin store

3. Search for "PDF PDF Merge and Compress Tool" 

4. Click "Add to Firefox"

5. Click the extension icon on the browser toolbar

6. Drag your PDF file into the extension window

7. Reorder as needed

8. Click "Merge" and save the generated file'

Note:  As a best PDF merger for Windows 11. This works even when you are offline after installation. The extension does not send your files anywhere—everything stays on your computer.