Can screen sharing from different networks be used?

hi :)

I was able to do screen sharing between my MacBook and Mac when the computers next to each other and when both are connected to the same wifi network.

When I get home with the MacBook (and the Mac stays at work) he notices that the connection has been severed.

Can't I use screen sharing when computers are on different networks?

The explanation explains that I can do screen sharing from anywhere.

What am I doing wrong? Or am I okay, which is just not possible?

Thanks in advance