If you wish to transfer your WhatsApp account to a new number, please do not delete your account. Use the Change Number feature instead.
You can delete your account from within WhatsApp.
Open WhatsApp and go to Settings > Account.
Select Delete My Account.
Enter your phone number in full international format and select Delete My Account.
Note: This is the only way you can delete your WhatsApp account. We cannot delete your account for you.