A charged particle in an electric field experiences a force and will accelerate (if there is a net resultant force).
If the charged particle is at rest or if the electric field is parallel to the particle’s motion, the magnitude of velocity of the particle will change.
When a charged particle is placed in an uniform electric field, in absence of all other forces, it will experience an acceleration in the direction of the field lines.
$F = ma$
$qE = ma$
$a = \frac{qE}{m}$
All laws of Kinematics can be applied to the motion of the charged particle.