How do I turn off do not disturb

Swipe Control Center down from the top right corner. Find the Focus button and tap. If a Focus profile, in your case "Do Not Disturb" is highlighted, tap to disable.

If Do Not Disturb activates automatically, you must delete the time schedule.

Go to: Settings > Focus > Do Not Disturb > Find Time Schedule, tap in and choose to delete.

You can read more about the Focus function on your iPhone here:

Use Focus on your iPhone or iPad - Apple Support