In Microsoft identity, the user.principal has claims. One type of claim is a role. Any identity system can build the principle. Typically they will have a place to add claims. The identity system supports defining a role provider. The provider may support crud operations on the user roles, but this is not required.
The database based individual identity supports roles, but only includes templates for login, logout and register. If you want roles, you will need to design the admin site.
You should read the docs.
https://learn.microsoft.com/en-us/aspnet/core/security/authentication/?view=aspnetcore-6.0