If you have tried to rotate pages in Acrobat using the Rotate View (View > Rotate View > Clockwise/Counterclockwise) options you may notice that after saving and reopening the document, the PDF doesn’t retain your rotation. To permanently rotate pages in Acrobat:
- Go to Document > Rotate Pages
- In the Rotate Pages menu select All Pages and choose the rotation direction.
- If you save the document and reopen it, your PDF will retain the rotation settings
Source: Acrobat Tutorial