iPad notification icon

You have enabled Assistive Touch.

To disable this feature:

Settings > General > Accessibility > Touch > AssistiveTouch > Assistive Touch - set to OFF

Additional about Assistive Touch can be found within the iPad User Guide:

Use AssistiveTouch on iPad - Apple Support

Perhaps appreciate that the Apple Support Community is a user-to-user technical forum. Other than the site Moderators, Apple neither monitor nor participate within this community. Contributors here are all end-users, just like you.

If you are having difficulty disabling Assistive Touch, perform a forced restart of your iPad - as this will often clear an isolated software issue.

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.

After the restart, you can try to disable Assistive Touch.