Blocking callers on a Desktop Computer

I am aware that on an iPad and an iPhone you can block a caller. This will stop any phone calls, messages or other attempts to get to you. I have set this up and the caller blocking seems to work.

What I would now like to do is complete the set by blocking via my Desktop computer. I do not see any settings that allow me to turn this off / on anywhere I looked - including

a. Contacts

b. Messages and contact details

Does anyone know how to check that this is active on a desktop computer and if not, how to set it up?

Thanks a million.