Merge PDF File means combining multiple PDF files into a single PDF file. It is easy to use and understand by OSTtoPSTAPP Merge PDF Tool. A PDF file can be locked or unlocked to prevent editing, printing, and copying. You can combine many documents into one using Merge PDF Tools. If you merge multiple PDF files into one PDF file, you can easily store and review them. Because of the straightforward user interface, it is highly simple and easy to use. Additionally, a free trial may be available to test the functionality. This software is compatible with all Windows OS versions, including 7, 8, 8.1, 10, 11, Vista, and XP. Install the trial software.