You can add the RecordTypeId field to your page in a Field Editor, mark it as Required, and Render As Picklist. 

Then wrap the rest of your page’s content in Conditional Rendering based on the RecordTypeId. If RecordTypeId is A and not blank, then show some areas. If RecordTypeId is B and not blank, then show some areas. 

Thanks for the reply Zach. I have another question, if the record is new and there will not be an existing record to show the record type. How could I overcome this?

I’m not sure what you mean - whether you’re creating a new record or editing an existing record, the RecordTypeId field should be on the same Model as the rest of the fields on your record that you want to edit, and the field should provide you with Record Type options to select.

Hi Zach, Ignore my last question I realized it doesn’t make sense
Thanks for the answer it resolved my problem.