https://www.cnet.com/news/spacex-crew-dragon-mission-to-iss-delayed-yet-again/

The uncrewed test flight to the International Space Station is designed to check how the launch, orbital, docking and landing systems function before actual astronauts take a ride to space inside the capsule. 

Crew Dragon is part of NASA's Commercial Crew program, which also involves the Boeing Starliner. The space agency is hoping to bring astronaut launches back to US soil for the first time since 2011. Astronauts visiting the ISS have been hitching rides on Russian spacecraft.