I am curious to know about how rockets or an object lands on the moon when there isn't any air (atmosphere) and the gravity is low.
Rocket engines (unlike jet engines and internal combustion engines) are designed to work without drawing air from outside. A moon lander carries 2 tanks: one filled with propellant, the other one filled with an oxidiser. The rocket engine combines these two and ignites the mixture. The exhaust product provides thrust both in an atmosphere and in a vacuum. Thrust may be slightly higher in a vacuum. The thrust is used to reduce the speed of the spacecraft to near zero, enabling a soft landing.
Rockets thrust works because of conservation of momentum, which is a fundamental law of our universe. When hot gasses are pushed out of the rocket, they exchange momentum with the rocket in the opposite direction. As a result, rockets don't need to "push" against anything on the business end. It's often misunderstood as a wing or helicopter rotors "pushing" against the air, but that isn't how rockets function. For some chemical rockets, if they require an oxidizer that is needed for creating hot gases, then it is carried inside the rocket.