Upvote:4
In places where hotels are required to register their guests with the local authorities, they will ask for the ID of all guests. Hence all guests might not need to be present to check-in, but their ID's will. Other hotels might just ask for one ID. This is assuming that all guests begin their stay on the same night.
In your specific case you should not need the other person to be present, or their ID for that matter, since you will effectively be alone on the first night. You should of course explain to hotel staff that another person will be joining you for the remaining period of your stay, and again this should cause no problems. It is indeed a very common situation.