Question

if i apply the force on the wall then force will be 0 but it doesnt mean that force is not applied. so is f=ma wrong?

Answer 1

You apply a force in the wall.. and wall do the same it applies the force on you. That's the reason the wall don't get displaced from its original position. Thus .. it's all safe.. the reaction is balanced by the force exerted by the wall

Answer 2

nope . force will not be zero . u will also experience an opposite force from wall if u apply force on it and its magnitude will be same as the magnitude of force applied by you .