Electric Field is the electric force experienced by a unit charge.
The electric force is calculated using the coulomb's law, whose formula is:
F=k∣q1q2∣r2F=k\dfrac{|q_{1}q_{2}|}{r^{2}}F=kr2∣q1q2∣
While substituting q2 as 1, electric field becomes:
E=k∣q1∣r2E=k\dfrac{|q_{1}|}{r^{2}}E=kr2∣q1∣
SI unit of Electric Field is V/m (Volt per meter).