To rotate the Page View
Choose View > Rotate View > Clockwise, or click the Rotate Clockwise button in the View bar, to rotate the page view clockwise.
Choose View > Rotate View > Counterclockwise, or click the Rotate Counterclockwise button in the View bar, to rotate the page view counterclockwise.
Notes
You can change the page view in 90-degree steps. This does not change the document itself, it is just a different viewing mode.
To really rotate page images in 90-degree steps, choose Pages in the Navigation Panel, right click, choose Rotate and specify which pages to rotate. See Page Operations.