You can curve your projectiles in mid-air to hit tricky targets. Whenever you make a ranged attack roll with a Warmage cantrip or a weapon that has Thrown, you can add or subtract a d4 from the d20 roll (to a maximum of 20 or a minimum of 1). Increasing the d20 roll to a 20 doesn't score a Critical Hit. You can choose to use this feature after making the attack roll, potentially causing the attack to hit.
You can use this feature a number of times equal to your Intelligence modifier (minimum of once). You regain one expended use when you finish a Short Rest and all expended uses when you finish a Long Rest.