"Which" is used to give more information about something.

 

His best movie, which won several awards, was about the life of Gandhi. 

  "That" cannot be used instead of "which" in this meaning. ✓

"That" 👉 is used to introduce a clause  without giving more information .

• There are lots of things that I need to buy before the trip.✓

• the people that live next door .  ✓