If you wish to use the intel crocus driver, as of August 2021 you need to use an environment variable when starting X, MESA_LOADER_DRIVER_OVERRIDE=crocus
The intel iris driver should already be the default.
For the old i965 driver, 'glxinfo -B' will report
OpenGL vendor string: Intel Open Source Technology Center
For crocus and iris it will report
OpenGL vendor string: Intel