Disable Email From Login

Hi, i would like to disable the email so the customer can login with 10 digits (for example) numbers for a username and the password that i can send them. is it possible?

Hi, i would like to disable the email so the customer can login with 10 digits (for example) numbers for a username and the password that i can send them. is it possible?

I am afraid, additional custom development work is required to create this feature.