7MTT just requires "credentials" of the "Windows system" on which the tool is installed. Basically, any user who is member of the windows admin group can login. Even if you have forgotten, just use any other account.
Example scenarios:
If you are a member of the Windows "Administrator group" and if you are accessing the tool (web interface) from the server on which it was installed. Just double-click the 7-Mode Transition Tool icon on your desktop. As long as you remember your Windows login credentials you should be good. (Or, Simply create a user and add it to the 'admin group').
If you are member of the Windows "Administrator group" but you have not installed the tool, then:
Use a supported browser to navigate to one of the following URLs:
https://IP_address:port/transition
http://IP_address:port/transition
If you are member of the Windows "Administrator group" and if you are accessing the tool (web interface) from another computer, then:
Use a supported browser to navigate to one of the following URLs:
https://IP_address:port/transition
http://IP_address:port/transition
https://docs.netapp.com/ontap-9/index.jsp?topic=%2Fcom.netapp.doc.dot-7mtt-isg%2FGUID-0B09608A-0F27-4FA2-91CA-18E8DDDCBA9C.html