How does an electric field affect the movement of a charge?
The electric field will exert a force that accelerates the charged particle.
The electric field has a direction, positive to negative. This is the direction that the electric field will cause a positive charge to accelerate.
If a positive charge is moving in the same direction as the electric field vector the particle's velocity will increase. If it is moving in the opposite direction it will decelerate.
If a negative charge is moving in the same direction as the electric field vector the particle will decelerate. If it is moving in the opposite direction it will accelerate.
If a charged particle is moving between parallel electric plates and its velocity is initially parallel to the plates it will be deflected toward the plate with opposite charge and its velocity vector will increase in magnitude.