"He wears a shirt."
Translation:O bir gömlek giyer.
This is just not how the language is used in daily life. If someone asks "what is he wearing," you would say "O tisort giyiyor" with "O" being optional and not common in this case. The present tense of "he is wearing" is giyiyor.
Gomlek is a button up shirt. Giyer in the given answer really means he will wear a gomlek (like at the event we are going to tonight).