Checked baggage (also called cargo baggage) is kept and transported in the airplane’s cargo hold.
This category is usually composed of larger (and in most cases more weighty) items like a bigger valise, sports gear, outsized items, musical instruments, and everything else that airlines permit to transport on a passenger airplane, and cannot be carried to the airplane.
Checked baggage needs to be given to the airport employees when checking in for the flight and will be unapproachable to you during the flight. That is why cautious and considerate planning while packing is going to save you from unpredicted problems during the trip.
For example, if there are medicine or documents that you may need in the course of the trip, then the best variant is to carry them in your cabin bag.
Please, take some time to go through the baggage allowance guidelines of the airline you’re going to travel with to find out the allowed count, size, and weight for every type of item you are going to take on the trip.