You need to register USTRUST to use the DPLUS system like REF001 and REF030.
You can register here : http://www.dstargateway.org/D-Star_Registration.html
If you only want to use XLX DSTAR systems, you do not need USTRUST registration
To use DMR, you need a registration
For European DMR registrations : https://register.ham-digital.org
For rest of the world : https://radioid.net/register#!