A store or restaurant company that has lots of stores in different places is called a "chain". Each store in the chain is called a "location". For example a representative from such a company could say:
We have over 300 locations across the U.S. and Canada.
You use the word "location" in this way when you're talking about the company as a business. In everyday life, when you want to talk about one store or restaurant in a chain, you just call it a "store" or a "restaurant".