Where can the homeless use their CalFresh benefits?

The short version: The homeless can use their CalFresh benefits any place any other recipient can use CalFresh, and a few other places as well:

At homeless shelters or soup kitchens, if they so choose: Homeless people can pay for meals with CalFresh benefits at some soup kitchens and homeless shelters authorized by USDA. [7 C.F.R. § 274.7(g)(4); MPP § 63-604.5.] No one can make a homeless individual give CalFresh benefits to the soup kitchen or other emergency meal provider. A soup kitchen or emergency meal provider cannot make people who get CalFresh pay for meals if other people get those meals free. Soup kitchens and other emergency meal providers cannot make people pay with CalFresh for food that they got for free or for any of their costs cooking the food or running their place. They can only request that homeless people voluntarily use their CalFresh benefits to pay for meals, and cannot ask them to pay more than the average cost of meals at the shelter. [See, generally, 7 C.F.R. § 278.2(b).]

For prepared food at participating restaurants and grocery stores: Homeless people may also use their CalFresh benefits at certain restaurants and grocery stores to buy prepared meals through the Restaurant Meals Program.  Effective September 1, 2021, the Restaurant Meals Program is statewide.  [ACL 21-100.]  EBT cards must allow all CalFresh recipients who are eligible for the Restaurant Meals Program to utilize benefits in all Restaurant Meals Program authorized restaurants statewide. [ACL 18-24.]