What is the admin center?
The Microsoft 365 admin center is where you manage your business in the cloud. You can complete such tasks as adding and removing users, changing licenses, and resetting passwords.Source: https://support.microsoft.com/en-us/office/admin-center-overview-fa715fa8-6eda-456d-b177-d1c156edd1b3
Admin center resources
365 Training Portal feedback
Our goal is to keep the training portal as up-to-date and useful as possible. Please use the feedback form to let us know about any broken links or updated resources, or to suggest additional resources.