Question

Please give me answer why friction is does not depend upon area with example

Answer 1

Although a larger area of contact between two surfaces would create a larger source of frictional forces, it also reduces the pressure between the two surfaces for a given force holding them together. Since pressure equals force divided by the area of contact, it works out that the increase in friction generating area is exactly offset by the reduction in pressure; the resulting frictional forces, then, are dependent only on the frictional coefficient of the materials and the FORCE holding them together. 

If you were to increase the force as you increased the area to keep PRESSURE the same, then increasing the area WOULD increase the frictional force between the two surfaces.

Answer 2

the value of frictional force doesn't depends on area. It depends on the coefficient of friction, mass of the body or say the contact force experienced by it, &its acceleration (if any).
You can also understand it this way, Friction is a force & from Newton's 2nd law we've derived that F=ma.. so frictional force depends on mass & acceleration of body. The experimental formula of friction is (mu)N where, mu is the coefficient of friction while N is the normal contact force. You'll notice that area is not there in any of these formulas directly or indirectly... hence, mathematically we can say friction never depends on area but it depends on the nature of medium(mu).