How do I Turn off Do Not Disturb.

Use Do Not Disturb with Focus on your iPhone or iPad - Apple Support

I would prsume the opposite of:

Turn on Do Not Disturb

1. Go to Settings > Focus.
2. Tap Do Not Disturb.
3. 
   
4. 
5. Under Turn on Automatically, set Do Not Disturb to turn on
6. automatically at a certain time, location, or while using a certain app.

To turn on Do Not Disturb from Control Center:

1. Open Control Center on your iPhone or iPod touch, or on your iPad. 
2. Touch and hold Focus, then tap Do Not Disturb.

To simply turn it off, go to the Control Center and tap the little round picture icon on the Focus button. If you tap an hold, it will bring up a lot of other options which you don't need to just turn it off.

It's not something that can be removed from the Control Center. The name may show as something else (the name of the currently active Focus). So, it could be "Do Not Disturb" or "Driving" or something else.

I believe the picture in this article shows the default configuration of Control Center:

Use and customize Control Center on iPhone - Apple Support