please help me. I want to clear the balance in my app store account

Here are two ways you can remove all your Apple ID (Apple Account) balance:

1) Spend it:

If your store credit is less than the cost of a single item on the iTunes Store, App Store, or iBooks Store, and you still have a valid payment method for that country, you can add the payment method to your account [ how to add a card --> https://support.apple.com/HT201266 ]. When you buy an item it will use the remaining store credit and the rest will be charged to the payment method. Buy something like a music track which you can download and also keep a backup copy. Anything purchased may not be available for re-download once you change countries but as long as you have your own copy you will always have it.

This solution used to be part of Apple's official documentation but has been removed even though it is still a perfectly feasible option. It results in you getting to spend your balance and keeping it in the form of a purchase instead of donating it to Apple.

2) Give it to Apple:

"If you still can't change your country or region, or you have less store credit than the cost of a single item, contact Apple Support." Apple will remove the balance and keep it.

Click here --> https://support.apple.com/choose-country-region/media-services Select your country, then a product such as billing. If you do not see your country, see if there is an "other" listing for that region. If you don't see an option that handles your issue then keep experimenting with selections until you reach one that gets you a chat session or a telephone call and get the representative to redirect you.

Or call Apple Support --> https://support.apple.com/HT201232

References:

Click on this link to read full information about requirements for changing store country:

Change your Apple ID country or region --> https://support.apple.com/HT201389