Steps to link a Battle.net account to a Humble Bundle account.
Follow these helpful tips to secure your account from hackers
Transfer Battle.net Balance between two separate Battle.net accounts.
Information about consolidating Battle.net accounts, and how to play on multiple Battle.net accounts at the same time.
How to attach an Authenticator to your Battle.net account
Information on where to update your Activsion Account Email
It is not possible to move a Call of Duty account to another Battle.net account
Troubleshooting steps for issues while linking a PlayStation Network, Xbox Live or Nintendo Switch account to a Battle.net account
An authenticator is on the Battle.net account that you did not add.