The location is using the 'FREE BASIC' plan and that solution can only work with this option so it is auto checked and hidden.

But i think what you want can only be done using the PRO plan with the free trial option. This way users can get 30 minutes for free if they accept the terms, others can log in with a username and password. (you can turn off the prepaid voucher and credit card modules if you dont want to sell accesses)

However you can only have 2 master accounts per location (who can log in for free with a username and password).

Currently we don't have a solution where you can 'create' logins, however we are planning to do so, but there is no ETA for this,