hand in
phrasal verb.to give a piece of work or a document to someone in authority, like a teacher or a boss.
phrasal verb.to submit a completed assignment, document, or item to a person in a position of authority for review or processing.
“Please hand in your homework by Friday.”
“After finishing the exam, the students walked to the front of the room to hand in their papers.”
“The employee decided to hand in his resignation after receiving a much better offer from a rival firm.”
often used with school assignments, official forms, or legal documents.
contrast with 'give in' (which can also mean to surrender) and 'submit' (the more formal equivalent used in academic or professional writing).
when the object is a pronoun like 'it', it must go between the verb and the particle.