Besides meaning "receive," "become," and (for casual
conversation) "understand," get can also mean answer
or respond to a ringing phone or someone who's
at the door.

Examples:

The phone's ringing, but I can't get it just now. Can you?

I hear the doorbell. Can you get it?

There's someone knocking on the front door, but I'm not
going to get it. I think it's a salesman.