Fetching details from the dictionary...

to put in; to let in; to take in; to bring in; to insert; to install (e.g. software); to set (a jewel, etc.); to ink in (e.g. tattoo)
to admit; to accept; to employ; to hire
to accept; to comply; to grant; to adopt (a policy, etc.); to take (advice, etc.); to listen to; to pay attention to
to include
to pay (one's rent, etc.)
to cast (a vote)
to make (tea, coffee, etc.)
to turn on (a switch, etc.)
to send (a fax); to call
コーヒーに砂糖を入れる?
Do you put sugar in your coffee?
かばんに本を入れて出かけた。
I put books in my bag and went out.
部屋に新しい空気を入れるために窓を開けましょう。
Let's open the window to let fresh air into the room.