Why isn’t bedtime on my clock app?

In iOS 14, as SravanKrA has indicated there are changes; on the Clock app, if you go to the Alarm tab, (and you have already setup a Sleep Schedule via the Health app,) you will see a Sleep/Wake Up Alarm with a link to CHANGE. This will take you to the Bedtime settings.

source: Set an alarm on iPhone - Apple Support

With iOS 14 it is part of health app.