You can create a document with a single page orientation. All pages receive the orientation of the first page of the document. When your document contains mixed page sizes, all pages will be rotated regardless of their page size. This is a rotation on document level.
For example
The first page is a landscape page. When you apply this option, then all portrait pages will be rotated to become landscape pages.
Click [Pages] - [Rotate to align].
Select to rotate to the left or to the right.