iPad not rotating

Hello! This may be because rotation lock is on. To fix this, swipe up from the bottom of the screen to go to the control center, and tap the symbol that looks like this:

Once you've done that, the problem should be fixed. If not, check out this article: Rotate the screen on your iPad - Apple Support

If that doesn't help, it may be a problem with the gyroscope or accelerometer in your iPad. Those find and detect motion.

Lock or unlock the screen orientation

You can lock the screen orientation so that it doesn’t change when you rotate iPad.

Open Control Center

Swipe down from the top-right corner of the screen, then tap.

When the screen orientation is locked,  appears in the status bar.