You are trying to send a creature you can see to another plane. The target must make a Charisma save and pass it successfully, otherwise it will be exiled.
Banishment 5e
Level: 4th
Classes: Warlock, Cleric, Sorcerer, Paladin, Wizard
Casting Time: 1 Action
Range: 60 feet
Components: V, S, M
Duration: Concentration, up to 1 minute
If the target is an aboriginal in your plane, he is exiled to a harmless demiplane. During the demiplane, the creature is disabled. When the spell ends, the target reappears in the space before being exiled. If the space is occupied, it will appear in the nearest unoccupied space.
If the target is not an aboriginal in your plane, he will be banished back to his home plane with a slight “pop”. If the spell ends before 1 minute has passed, the target will reappear in the space before he was exiled. If the space is occupied, he appears in the nearest unoccupied space. If the spell ends after 1 minute, the target will not return to the original place.
When using a 5th-level or higher spell slot to cast this spell, you can specify an additional target for every 4th-level spell slot you use.