Player's Handbook

Searing Smite

1-level Evocation

The next time you hit a creature with a melee weapon attack, the attack deals an extra 1d6 fire damage to the target and sets them on fire. The fire goes out if the spell is ended.   At the start of its turns, the target must make a Constitution saving throw. On a failure, it takes 1d6 fire damage. On a success, the spell ends. If the target or a creature within 5 feet of it uses an action to put out the flames, or if some other effect puts out the flames, the spell ends.
At higher levels: The initial extra damage dealt by the attack increases by 1d6 for each slot above 1st.