I've tried to find a way to enable 2 factor authentication for login to the Google Apps management console (`admin.google.com`), but can't seem to find it. (I already have 2 factor auth for my users on the domain, so it is not for domain users but for the admin console I want to enable it.)

Have googled for it and searched here also, but can't seem to find the answer/way to enable it.

Can anyone help, please?