Camera for iPad Air with 12.4.5 ios

The Camera app cannot be deleted.

Do a Spotlight search.

Also check if you have restrictions set:

Settings > Screen Time > Content & Privacy Restrictions > Allowed Apps > Camera : ON?

Note: Content & Privacy Restrictions must be enabled to see and make changes.

There is no reset for a forgotten restrictions passcode. You will have to erase your iPad using your home computer with iTunes and this is important - You cannot restore from backup. You will have to set up the iPad as new. If you have messages, photos, etc. synced in the cloud, you can turn those services back on. If you don't, your data is gone.

This link explains how to restore the device --> If you forgot the passcode for your iPhone, iPad, or iPod touch, or your device is disabled - Apple Support

Spotlight search: With one finger swipe down from the middle of the Home screen.

There is no reset if you do not remember the restrictions passcode,

you have to use the computer iTunes and restore the iPad as new.