After you have downloaded a document, you may wish to save it to a location on your computer.  To do so, select File > Save a Copy located in the main toolbar.

After you have clicked on "Save a Copy", you may receive the dialogue box below.  If so, click on "OK" and save the document as any file name and under any folder on your computer as you wish.

For further information about saving Adobe Acrobat PDF documents, consult "Help" under the main toolbar in the Adobe Acrobat Reader.