[mothered]

Increase my online privacy; even though I haven't truly discovered yet how can they see my MAC address.

Not to dissuade you, but generally your hardware (adapter, etc.) MAC address will be hidden unless they are on your local network.

but generally your hardware (adapter, etc.) MAC address will be hidden unless they are on your local network.

This Is correct. MAC addresses are non-routable.

Simply put, your device connects to your router, and It's your "router's MAC address" that takes over. From there, your router communicates with your ISP's servers, hence It's "their MAC address that's visible". From this point forward, It's your ISP's MAC address that may be disclosed to every website you visit.

Oh, I didn't know that, thank you.
That's why I will always use forums.

You're always welcome.