What is the formula for the force of attraction (F) between two objects of masses M and m which lie at a distance d from each other, where G is the constant of proportionality called as universal gravitation constant?

The law of gravitation states that the force of attraction(F)  between any two objects is proportional to the product of their masses M and m and inversely proportional to the square of the distance (d) between them. 

The gravitational constant is the proportionality constant used in Newton’s Law of Universal Gravitation, and is commonly denoted by G. 

$$ G = 6.673 \times 10^-11 N m ^2 kg^-2 $$

F=$$\frac{G(M\times m)}{d^{2}}$$