In this Mage armor 5e you actually touch one of your willing creatures who is not wearing an armor, and also a protective magical force that surrounds it until the end of this dnd 5e mage armor spell. Actually, the target base AC would become 13 + its dexterity modifier.
The spell will end it if the target dons armor or else you would dismiss the spell like an action.
Check out about: forbiddance spell 5e
Attributes Of D&D 5E Mage Armor
|Casting Time||1 action|
|Components||V S M|
|Material||A piece of cured leather|
|Target||A willing creature who isn't wearing armor|