The front squat is a basic lower body strength exercise.
Place the bar on the front of the shoulder, hands lightly gripping the bar just outside of the shoulders and the elbows up at 90 degrees. Arch the back hard, particularly the upper back and take a deep breath in. Engage everything in your core and keep it tight. Set your feet between hip and shoulder width with your toes slightly turned out. Keeping your chest up and everything engaged break at the hip and knee together and descend into the bottom of the squat. Full range of motion for the squat is with your hamstrings completely covering your calves, feet flat on the floor, whilst maintaining the arch in your low back. If full range of motion cannot be achieved then you need to work on mobility. Upon reaching the bottom of a squat drive up aggressively with the legs ensuring you are keeping the chest up throughout with the weight towards the rear of the foot.
When performed with full range of motion the front squat is a great strength builder of the legs, trunk and back extensors whilst promoting full range of motion to the hips and ankle. With the bar in the front of the shoulders it places more stress on maintaining a upright torso throughout the lift. The more upright position also pushes the load slightly more onto the quads and will have a great carry over to your cleans.
There are infinite programming possibilities when it comes to the front squat but more commonly than not for strength gain 1-5 reps are used. However, due to the carry over for the clean moderate weights can be used to work on positioning, timing and speed.