To the hotel. Can a double room accommodate four people?

Ordinary hotels can, because they don't do rounds, but it's best to submit only two certificates when checking in.

The key to this problem is mainly to look at the hotel.

Some hotels are not very strict, but they are ok. Once before, three people wanted to add beds, but later the front desk told me to change you to a bigger double room, and a bed would be fine. The room also gave us a big one.

So I suggest you send an email directly to the hotel to ask, generally the hotel will reply faster! It would be more convenient if it was booked on booking. Just let the customer service staff who booked the ticket contact you directly!