Will an 11 speed Shimano cassette fit/ work properly on a Shimano 10 speed free hub?
Is it a Shimano 10 speed “only” freehub?
Will an 11 speed Shimano cassette fit/ work properly on a Shimano 10 speed free hub?
It depends. If you have a 10-sp freehub, there are a couple of shimano 11-34, 11-sp cassettes that can work - specifically the CS-HG700-11 and the CS-HG800-11.
https://bike.shimano.com/en-EU/product/component/ultegra-r8000/CS-HG800-11.html
https://bike.shimano.com/en-EU/product/component/shimano105-r7000/CS-HG700-11.html