A coin and feather are dropped together from the same height in a vacuum

The earth exerts the gravitational force of attraction on both coin and the feather. Due to the gravitational force, both of these objects start falling toward the ground with acceleration due to gravity.

The acceleration due to gravity on the earth can be given as:
$\mathrm{g}=\frac{ \mathrm{GM}}{{\mathrm{R}}^2}$

Where M is the mass of the earth and R is the radius of the earth.
Since the acceleration due to gravity does not depend on the mass of the falling object, we can say that both coin and feather will have the same acceleration and reach the ground together. However, this holds true only in a vacuum. In our day-to-day life, we observe that coin reaches the ground before the feather. This is due to the presence of air resistance.