Tree roots don't always grow deep in the ground. In some cases, they are shallow and rise above the soil causing tripping dangers and bumps in the lawn. If you want to cover them up and make the area safer, plant and grow grass over the top of the roots. This is not difficult and will put the roots back where they should be, which is under ground.
Dig up the soil in between the roots with a hoe. Dig down only a few inches because you don't want to disturb any other deeper roots.
Add top soil to the spaces in between the roots to bring the ground level several inches above the level of the roots. Use a hoe to mix it with the soil, covering the roots as well. The tree roots will keep enlarging over time, so you want to make this repair last for several years. The more soil you can put on top, the longer the fix will last. Increase the height of the soil above the roots by at least 3 inches, tapering it down after you get beyond the root issue. Rake it out smooth.
Cast seeds over the area around the tree. Use your hands because it is such a small area. Toss seeds until coverage is about 16 seeds per square inch. Mainly you want enough seeds to cover the soil without overlapping each other.
Sprinkle one-quarter of soil on top of the seeds. Normally you could just rake the seeds into the soil gently to cover them, but this might uncover the roots, so it is better to sprinkle soil on top.
Set up sprinklers to water the seeds daily and keep the soil damp until sprouts grow. Once you see grass growing, reduce watering to twice a week.