The best way to delete your Autodesk account is to start the process in the following way:
1. Log into the account you want to delete at tinkercad.com.
2. Once logged in, you may go your profile page on Tinkercad (option under your avatar at the top right), which should have a link to profile.autodesk.com security section. Click the profile security section link in your Tinkercad profile and you will see the profile.autodesk.com/security page for your account.
3. In the Security tab, you may choose to "Start deletion" of your account and data.
Also, here is some more information about deleting your account: https://knowledge.autodesk.com/customer-service/account-management/account-profile/account-security/delete-your-autodesk-account