iPad. Change the name on Settings

Presumably you refer to the device name. This can be simply changed in iPad settings:

Settings > General > About > Name - set as required

After setting the chosen name, close the settings App - then perform a forced restart:

Force restart iPad (models with Face ID or with Touch ID in the top button)

If your iPad doesn’t have the Home button, do the following:

1. Press and quickly release the volume button nearest to the top button.
2. Press and quickly release the volume button farthest from the top button.
3. Press and hold the top button.
4. When the Apple logo appears, release the top button.

Force restart iPad (models with the Home button)

Press and hold the top button and the Home button at the same time. When the Apple logo appears, release both buttons.