Trying to update WhatsApp with new Apple ID. When I enter my password, it keeps saying my account is disabled. So I have to reset it, and when I reset it, the same problem exist.
Apparently someone tried to get unauthorized access to your Apple account (by entering incorrect password many times, entering wrong answer for security questions etc.). In such instances, Apple disables the account to preserve the security of your account.
From the Apple Support document, If your Apple ID is locked or disabled:
If you or someone else enters your password, security questions, or other account information incorrectly too many times, your Apple ID automatically locks to protect your security and you can't sign in to any Apple services. You can unlock your Apple ID after you verify your identity.
To unlock your account, regain access, and thereby continue to install/update apps, follow the on-screen instructions on your trusted device(s) to reset your password.