How can I clear my Apple Account balance?

We can't, but you can contact Apple directly here and they can:

Contact Apple Support - Apple Support

If you are looking to change regions, here is some more information that may help you:

Change your Apple Account country or region - Apple Support

If you are changing regions:

PART 1:

Cancel your subscriptions and wait until the end of the subscription period. ⇣

PART 2:

Make a request to zero out any remaining balance on your account by contacting Customer Support by phone:

• 1-800-APLCARE.
• Contact Support.

PART 3:

Click ▶︎ Change Region for step-by-step instructions. 🌐

Good luck! 👋🏼😉