I believe that is a variety of creeping Charlie. Spray with Weed-b-Gon Chickweed, Clover, and Oxalis Killer every 6 weeks or so.

Thank you.

Looks like what I have in my back lawn too. Does it bloom small purple flowers? If so, it's the ground cover called Bugleweed . Garden centres sell it. It's very invasive. I spent hours pulling this out of my lawn and found this is the only way to stay on top of it. It comes out pretty easily after a rain. I seem to get less and less coming up every year.