order in
To order food online or over the phone to be delivered to one's home or workplace. A noun or pronoun can be used between "order" and "in" to specify what is being ordered. I really don't feel like cooking tonight. Let's just order in instead. Everyone in the office is ordering in burritos—do you want one? They're ordering pizza in for the slumber party.
order someone in (to something)
to command someone to get into something. The officer ordered Ann into the wagon. She didn't want to go, but the cop ordered her in.
order something in
to have something, usually food, brought into one's house or place of business. Do you want to order pizza in? Shall I order in pizza?