Definition
to officially register your arrival by signing in when you reach a hotel, etc.
註冊入住（酒店）
We booked in as soon as we arrived at the hotel.
我們一到達酒店就辦理了入住手續。
I booked you in before you arrived.
我在你到達之前就幫你辦理了入住。
They successfully booked into the hotel in Taipei.
他們成功地在台北的酒店辦理了入住。