can friction help in acceleration?? in any case?

Friction is a force opposing relative sliding motion of two bodies in contact (it doesn't oppose the contact, it opposes the sliding).

If the objects are initially stationary relative to each other, friction acts as a force of constraint, and we call that force of constraint, static friction or traction.

If pre-existing sliding motion exists, then the force of friction will oppose the relative sliding. We call this force opposing motion and dissipating energy as heat, kinetic friction or sliding friction.

Do realize that kinetic friction does not depend on any kinematics of sliding. It only depends on the normal force of contact, and on the mutual roughness/stickiness of the surfaces (coefficient of kinetic friction).

Similarly with static friction. There is a maximum deliverable amount of static friction. This maximum amount depends only on the normal force of contact, and the mutual roughness/stickiness of the surfaces (coefficient of static friction). Coefficient of static friction is usually a bit larger than coefficient of kinetic friction.
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How does friction affects acceleration?

Well friction is nothing more than one of our forces for which we need to take in to account when adding up as vectors all forces acting on an object.

Any force which goes unbalanced by a different force affects acceleration.