Introduction PDF Split Merge is a stand-alone tool for splitting, merging PDF documents,allows you to split large PDF files into smaller PDF files,and merge one or more PDF files. PDF Split Merge is offered as an easy-to-use GUI (Graphical User Interface) application, and command-line application. The split functionality lets you split one or more PDF files based on page groups, page ranges. The merge functionality lets you quickly combine a collection of PDF documents and page sets.