The Apple TV app provides a means to access multiple subscription services (in-app channels). Verify that your chosen content is part of the service that you subscribe to.
If you subscribe to Apple TV+, then you would have access to the full Apple TV+ catalog.
See your subscriptions overview - Apple
iPad, iPadOS 16
As iPad is a single-account-device, users would be automatically signed in for the Apple TV app, unless manually signed out. When signed in, any applicable subscription(s) will grant you access to that content.
For us to help you get to the cause, please disclose a show title that gives you these issues.
About Apple TV+ - Apple
Apple Originals - Apple TV+ Press
List of Apple TV+ original programming (episodic/series) - Wikipedia
List of Apple TV+ original films - Wikipedia
there is no help or contact feature on the app.
If you prefer to talk/chat to Apple Support staff instead, then go here: Get support - Apple Support.