Weeds taking over my backyard
Prince George's County Maryland
This is a weed known as creeping Charlie or ground ivy--it is a foreign weed classified as non-native and invasive. (Your lawn looks great, incidentally!) You'll want to address it ASAP.
Here's info about ground ivy: https://extension.umd.edu/hgic/topics/ground-ivy If it is too extensive to hand dig, use the herbicide recommended right away. Two applications spaced a couple of weeks apart may be necessary. This is a good time of year to get the most efficient use out of a "systemic" herbicide--which goes down into the root system of a perennial weed. In the fall, plants are moving resources down into their roots to store over the winter, and they will translocate the herbicide most efficiently to roots then.
Our website is a treasure trove of resources about lawn care. I hope you will take the time to explore it and it's many topics about lawns, as well as all about vegetables, fruit, and ornamental plants.