An invisible barrier of magical force appears and protects one creature or object of your choice within 60 feet. For the duration of the spell, as long as the target is within 100 feet of you, the target has a +5 bonus to AC and advantage on all saving throws, including against the triggering attack, and takes no damage from magic missile. The spells ends if you use a bonus action to end the spell, or if the target moves out of range.

At higher levels. When you cast Shield of the Archmage using a spell slot of 6th level or higher, the target gains an additional +1 bonus to AC for each level above 5th.