Adaxes Web interface is configured via the Web interface configurator. By default, it is available by the link like this:
Where host.domain.com is the FQDN of the computer where the Adaxes Web interface component is installed. Unfortunately, there is no easy way to determine on which computer in your environment the Web interface component with the Web interface configurator is installed. You can try checking Windows Programs and Features on computers to see where the Softerra Adaxes components are installed. Then, check IIS on these computers to verify if there are websites hosting the AdaxesConfig application present.
Once you find the Web interface configurator, you can use it to configure the required form in the required Web interface. For details on how to modify forms, have a look at the following tutorial: https://www.adaxes.com/help/CustomizeFormsForUserCreationAndEditing.