As a teacher, you may delegate certain admin roles, to your internal team. In such cases, you may share your admin password. Most often, this may lead to your password being misused.
Two factor authentication process, helps you control this misuse. You can set a limit to the number of times per month you can login to your admin account id.
Once that limit is crossed, instead of password an OTP send to your registered mobile number need to be entered.
To know, how to enable this feature refer to the enable two factor authentication support article.