Hi Therealbigpanda,
If I understand you correct, you are looking for an option which selects all the pages of the PDF at once. Am I right?
If yes, sorry to say there is no such option available right now in the mobile application.
However, you can manually select all the pages by clicking on each page one by one on your iPad.
Open the PDF and select "Organize Pages" tool. The click on each page one by one to select them.
Once all the pages are selected, you can change the orientation of all the pages at once.
Hope that helps.
Let us know if you have any questions.
Regards,
Meenakshi