in
1.
to give back sth that you no longer need :
You must turn in your pass when you leave the building.
2.
( especially NAmE ) to give sth to sb in authority :
They turned in a petition with 80 000 signatures.
I haven't even turned in Monday's work yet.
3.
to achieve a score, performance, profit, etc. :
The champion turned in a superb performance to retain her title.