The major difference between a 1s orbital and a 2s orbital is that The 2s orbital has a slightly different shape.
The 2s orbital is at a higher energy level.
The 2s orbital can hold more electrons.
The 1s orbital can have only one electron.

The 2s orbital is at a higher energy level.

Explanation:

1s and 2s are present in the s sub-orbital which surrounds the nucleus. The s sub-orbital has a spherical shape. As per the level of the energy, the sub-orbitals are numbered as 1s, 2s, 3s, 4s, etc. respectively. The difference among the sub-orbitals is based on their level of energy. 1s has less energy level than 2s. The radius of 2s is more than 1s.