How does the shared GPU memory work?

I'm somehow desperate to prepare for the new wave of games and I've rummaged through the functions of Windows 10.

My laptop has a 1050 ti with 2gb and a good chip with 512mb or so but now the interesting thing, the settings say, my shared gpu memory is 8gb

Now the question; Can I really work with this 8GB memory, is that a technology in Windows 10 that allows several GPUs to work together?

I'm overwhelmed and grateful for answers.

I don't know if this only applies to processor graphics, but some systems use your normal RAM as graphics RAM, for example my laptop has 8GB of RAM, but I can only use 6GB because of that!