Getting rid of moss
There may be several reasons you have moss in your lawn which include poor soils, shade, poor lawn care practices, acidic soils, etc. These conditions are unfavorable for grass so the grass thins out and the moss moves in.
You can eliminate the moss by raking and disposing of. However, if you want to get rid of it you need to correct the conditions that favor its growth. See above.
Begin by testing your soil for pH and nutrient deficiencies.
Options include planting grass, alternative groundcovers, and some actually cultivate the moss. There is nothing wrong with leaving the moss as it is. It makes a suitable and low-maintenance ground cover. Here is our page on moss http://extension.umd.edu/hgic/topics/moss-your-landscape