Adobe Acrobat Pro
Adobe® Acrobat® Pro software lets you deliver professional PDF communications. Create and edit PDF files with rich media included, share information more securely, and gather feedback more efficiently.
Combining/Merging PDF files
Adobe Acrobat Pro allows you to select multiple PDF files and combine them into a new, single PDF.
There are several ways to begin the process. Two of the easiest are to select Combine Files into PDF from the Acrobat Pro welcome screen...
...or to select File > Create > Combine Files into a Single PDF...
Next, you will see the Combine Files dialog.