A kilowatt-hour (kWh) is a way of measuring how much energy you use. This is what you see on your bill.
A kilowatt (kW) is the POWER something uses. An hour (h) is how long or TIME it’s used for
A kilowatt-hour (kWh) = the power x the time = the energy used
For example if you run a 1kW appliance for 1 hour you have used 1kWh of energy.