Hi Carolyn. I had a huge oak tree with giant roots showing. I completely covered the area with several inches thick of fresh topsoil, raked it out smooth, blending it into the existing grass and seeded it w/new lawn seed. Pamper the area until those seeds really take. Good Luck :)
You will need top soil over the areas where roots are near or at the surface. Then plant grass seed as you would in any other area or lay sod. We cover grass seed with hay to prevent the birds from eating away or turn the dirt over if it's a large area.