A 100% free toolbox for Windows that includes merging, editing, and converting. It processes files locally for maximum privacy. Apple Preview
Online tools are the fastest way to combine documents directly in your web browser. Most use a simple drag-and-drop interface. PDFsam: Split and merge PDF files. Free and open source combine pdf files into one file free download
The standard app on macOS can merge PDFs for free. Simply drag thumbnails from one PDF into another in the sidebar. PDF Merger & Splitter A 100% free toolbox for Windows that includes