This looks like a type of Chickweed (of which there are several species; blooms can help distinguish them). They are common winter weeds of lawns and gardens, as they grow in the cooler months and go dormant (or die completely) by summer. Because they germinate or begin growth in autumn as the weather cools, control measures are best applied then. For now, hand removal might be the most practical method if infestation isn't too extensive. Smothering is another option if the area they're growing in doesn't contain any other desirable plants. If herbicides are needed, you may need to wait until spring's milder temperatures to have treatments be effective. In that case, make sure Chickweed is on the product's label and follow its directions regarding timing of application and any recommended re-applications. More information about Chickweeds and their control can be found on this page: https://extension.umd.edu/hgic/topics/common-chickweed

Miri