Add +1 to your Charisma, up to 20, maximum.

Chose one of two effects: Once used, you must have a short or long rest before manifesting the Voices again.

You can spend 10 minutes inspiring your companions through the use of metamagical warlock arcane energy, shoring up their resolve to fight. When you do so, choose up to six friendly creatures (which can include yourself) within 30 feet of you who can see or hear you and who can understand you. Each creature can gain temporary hit points equal to your level + your Charisma modifier. A creature can't gain temporary hit points from this feat again until it has finished a short or long rest.

(or)

You can spend 10 minutes inspiring your companions through the use of metamagical warlock arcane energy, boosting their ability to fight. When you do so, choose up to six friendly creatures (which can include yourself) within 30 feet of you who can see or hear you and who can understand you. Their first attack action after hearing the voices of the Old Ones are then made at advantage. A creature can't gain advantage from this feat again until it has finished a short or long rest.