To share purchased movies with a Family Sharing group, the organizer needs to activate the “Purchase Sharing” option within Family Sharing. That option also has consequences for billing: with Purchase Sharing, all (future) digital Apple purchases are billed to the organizer. If financially compensating the organizer is wanted, but too much of a drag each time, then do not activate this option.
How to share purchases with your family - Apple Support
If Purchase Sharing is activated, then in the Family Sharing list on your device(s), you should see the other members. In turn, they would see your sharing account on their devices.
Subscription content is handled differently. Just go to the subscription service to access that.
If you can't find your family's shared content - Apple Support