Gravitational force is not a force of contact. Any object on the Earth or at least close to Earth, will experience a gravitational force. It is the weakest of the four fundamental forces, yet it is the dominant force in the universe for shaping the large scale structure of galaxies, stars, etc.
Newton’s Law of Universal Gravitation is used to explain gravitational force .The law can be explained as :
Every point mass attracts every single other point mass by a force pointing along the line intersecting both points. The force is proportional to the product of the two masses and inversely proportional to the square of the distance between the point masses.