注文をする

You use it just like any other 'noun + suru' verb. If you are at a restaurant, you might say 注文をしてもいいですか？ (May I order?). If you are talking about something you already did, use the past tense: 注文をした (I ordered). You can drop the を in casual conversation to just say 注文する. It is like the Swiss Army knife of shopping and dining.

Use it whenever you are the customer. Use it at a ramen shop when you're ready to eat. Use it when you are talking about that cool gadget you found on Amazon. Use it when you are at a bar and want another round. It works perfectly in professional settings too. If you are a clerk, you might ask a customer ご注文は？ (Your order?).

Do not use this to give someone a command or 'order' them around. If you want to tell your friend to clean their room, 注文をする will sound very strange. For that, you would use 命令する (meirei suru). Also, if you are just 'asking a favor' rather than buying something, use 頼む (tanomu) instead. Don't use it for ordering a hit on someone—that’s a different movie entirely!

Japan takes the art of the order very seriously. In many restaurants, you will find a small button on the table. Pressing it is the physical version of saying you want to 注文をする. There is a heavy focus on 'Omotenashi' or hospitality. This means the staff will often repeat your order back to you with extreme precision. It is a ritual of accuracy and politeness.

You will often hear 注文をお願いします (Order, please) when calling a waiter. In casual settings, friends might ask 何注文する？ (What are you gonna order?). If you are online shopping, the button usually says 注文を確定する (Confirm order). It is a word you will see and hear every single day in Japan.