You can combine PDF documents with Adobe Acrobat, not Adobe Reader.
In Create PDF service part of acrobat.com, you will be able to combine your PDF documents to a single PDF doc.
You can also do this with Acrobat Professional desktop application.
Note : in Acrobat.com service, you should be a premium subscriber, unfortunately this is not available for a free account.
Thank you very much for your time and your answer.
Thank you for your time and your answer