bedtime in ios14

Not all features are available on both iPad and iPhone - some features being limited to only one or other. Apple do not share their reasoning behind their hardware and software design decisions.

Apple have moved Bedtime function from the Clock App to the Health App. As the Health App is not available for iPad, the Bedtime function is no longer an element of iPadOS.

Apple do invite constructive feedback and feature requests via their product feedback portal:

Feedback - iPad - Apple

iPad do not have Health app like an iPhone so it's not available for iPad.

read here = > Set up sleep schedules in Health on iPhone - Apple Support