Eldritch Strike

As part of the action used to cast this spell, you must make a melee attack with your pact weapon against one creature within the weapons range, otherwise the spell fails. On a hit, the target suffers the attack’s normal effects, but the weapon can use a 1d10 die instead of it's normal die and the damage type is changed to force damage. 

You can make more strikes when you reach higher levels: two strikes at 5th level, three strikes at 11th level, and four strikes at 17th level. You can direct the strike at the same target or at different ones. Make a separate attack roll for each strike.