Can I use three room cards in a hotel room at the same time?

No, there is usually only one room card in a room.

A room in a regular hotel doesn't have two room cards, but if you need to enter the room, but your friend doesn't have a room card, you can talk to the front desk clerk and ask him to help open the door.

The main function of the room card is to open the door and insert the card to get electricity, and then all kinds of electrical appliances in the room can be used normally. Generally, each door will be equipped with a key, but this key will only be used if the door is locked or the card cannot be opened normally. Guests staying in the hotel can only get the room card when they open the room, and the mechanical key will not be provided to you. Generally, the hotel room card is about the same size as the bank card, and the hotel name and LOGO will be printed on it. Telephone and other information should be returned to the hotel when checking out. Of course, some hotels don't pay much attention to checking out and returning your card, or if you need compensation for losing your card, you can not return it to the hotel.