It uses NASA’s Deep Space Network. There are three stations around the globe (California, Australia, and Spain), spaced so that there is near continuous coverage for deep space missions. JWST points it’s antenna at the station that is currently in view.

However, the ground stations are shared between many missions, so they are not available for JWST all the time. Expectation is that JWST gets 8-12 hours/day of DSN time.