How do you crop a PDF in Acrobat ?
You posted to Acrobat Reader Mobile and you cannot crop in the mobile Reader.
If you are using the paid version of Acrobat DC, use the Crop tool. Details here:
Which app are you using?
Hope you are doing well. Per the description, I understand you want to crop pages from a PDF in Acrobat Reader Mobile.
Would you mind clarifying what you mean by cropping the PDFs? If you want to extract pages, you can use the organize page option to do so: Manage subscriptions — Acrobat for iOS Help
If you are referring to cropping the page, this feature is available only on the desktop version of the application. We would love to have your feedback: https://acrobat.uservoice.com/. This ensures that your feedback reaches our product team for them to review and implement in the upcoming updates.
Hope this helps.