Distance is a measurement of the length between two points. Distance does not include a direction. Measurements that do not include a direction are called scalars.
Displacement is the overall change of position of an object. Distance compares the ending position of an object to the starting point of the object. Displacement includes a direction. Measurements that include a direction are called vectors.
If you ran a lap around a standard track you would run a distance of 400 m. If we compare your ending position to your starting position we would find that those two positions are the same. Your displacement would be 0.0 m.