The free Adobe Acrobat Reader is a PDF viewer and does not allow to modify PDF files. Rotating a PDF and save changes would require to save a modified version of the PDF file, this is a premium feature available in Acrobat DC.
PDFsam Basic is the most popular offline PDF merger. No need to upload or share your PDF documents, keep them safe on your computer, away from prying eyes and easily merge them with PDFsam Basic. Completely free and open source, without time limits, without watermarks, simply free.
They are Windows launchers for PDFsam Basic, our free and open source application to split and merge PDF files.
PDFsam Basic is written in Java and requires a Java Runtime Environment to run (pretty much like a C# application requires .NET framework installed, a Python application requires a Python interpreter etc etc). Read more…
I just want to remind you that you can use the documentation as a valuable source of information about PDFsam where many HowTos can be found.
I updated the Wiki adding a simple tutorial on how to modify the amount of memory that PDFsam can use to minimize OutOfMemory errors.
Here is the link.