Hello Mike

This is Sedum acre, also called mossy stonecrop. It is an ornamental that escapes into lawns. One way to manage it is by hand removal, being careful to not leave any pieces behind, because the stems can root and continue to grow. Remove it before it flowers and sets seed, since it can easily seed itself.

There are chemical options. If using a chemical, crush the plants first so more herbicide is absorbed by the plant. 
As always, follow all label precautions and directions on any garden product used.

Here are details on Sedum acre and which chemicals can help.

https://www.canr.msu.edu/news/scouting_for_weeds_mossy_stonecrop