Assignment contracts in DFW

[Maria Lopez]

Hello, I’m a real estate agent in DFW. I have recently closed on a home where the seller had an assignment contract with her insurance agent (I was representing the buyer). We closed on it and her insurance agent received 12k from the transaction simply for listing the home. I am wondering how one can do this, and if this is something I should look into doing to expand my real estate business as an agent (assignment contracts that is)