Mirror Display Auto-Lock

Hello carey196,

On your iPad, go to Settings > Display & Brightness > Auto-Lock. You can choose Never or the time interval that you prefer.

Let us know if you have further questions.

Take care.

Hello carey196,

Welcome to Apple Support Communities. We understand that you want to auto lock the mirror display on your iPad. We are happy to assist.

It sounds like you want to lock the screen orientation. If so, please try the steps here: Change or lock the screen orientation on iPad - Apple Support

If you’re unable to use screen mirroring, please try the steps here: If screen mirroring or streaming isn't working on your AirPlay-compatible device - Apple Support

Let us know if you have further questions.

Take care.