Your spell Hex adds 1d6 damage to attacks you make. This includes Eldritch blast and Scorching Ray. Make sure that you always have Hex up, as long as you aren't in danger of losing concentration. You only have to use one spell slot on it, because once you kill someone who has been hexed, you can cast it again for free on another enemy.(Make sure you use re-apply Hex spell, it's separate from Hex.)
Hex, like every single Concentration spell, is a waste of time in Baldur's Gate 3 because of all the AoE damage, no-save surface effects, and going prone.