制服を着て

wearing a uniform

→ 制服
phrase Uncommon #16,816
wearing a uniform 着て is the te-form of 着る, “to wear,” and often connects to another action. With いる, 着ている means “to be wearing.”
JA: 制服を着て学校へ行きます。
EN: I go to school wearing a uniform.

制服を着ていたか?

Were you wearing a uniform?

— ミスティック・リバー (2003)

私は彼女に駅で会ったが、制服を着ていたので彼女だとわからなかった。

I saw her at the station, but I didn’t recognize her because she was wearing a school uniform.

私たちはみな、制服を着て登校する。

We all wear uniforms to school.

学校では制服を着ています。

I wear a school uniform at school.

彼らはみんな制服を着ていた。

They were all wearing uniforms.

お前がそうして制服を着てここで働いていられるのも俺のおかげだ!

The only reason you're able to dress in that uniform and work here is because of me!

— Article 15 (2019)

二人の警官が制服を着てやってきた

Two police officers came wearing their uniforms.

— ミスティック・リバー (2003)