"Check in" is done at a hotel/motel/hostel. Sometimes you can say it with any place that requires you to sign papers when you arrive, but often "sign in" is used for that. For example: "We're staying at the Bates Motel. I'd prefer to check in before midnight." "Make sure you sign in at the nurses office before you visit your friend." "Check" isn't used very often. We prefer "check out". For example: "Check out the motel to see if it's safe." "Check" is usually only used when you're actually looking at things on a list, and thus checking them off (i.e. making check marks next to them). "Let's check to see if you have everything. Fruits?" "Check." "Vegetables?" "Check." You get the idea.

Check-تحقق Chek-in-تحقق الأمتعة