A PDF file is one of the most widely used document types. It can be shared across multiple platforms, compressed into a smaller size easily, and cannot be edited without leaving a digital footprint.

From Adobe Acrobat to free online editors and built-in tools, here’s how to merge multiple PDFs into one document.

Most of us take PDF files for granted. Years ago, Adobe created a universal file format with their Acrobat software that produced documents which could be opened on PCs, Mac and Unix/Linux computers.