My iPad is under warranty what do I do to get repaired

https://support.apple.com/ipad/repair/service

Start there. Depending on where you are it may be better tomake an appointment at your local apple store and take it in, or there may be an authorized service provider around, or you may need to send it in.

One thing to be aware of is that generally, they don’t repair devices....you trade yours in for a replacement, and they may fix yours, later, and then use it as a replacement for someone else, to be sure to backup your device along with removing it from your iCloud. THere should be directions for doing that as part of setting up the appointment.