The hip adduction machine is made to isolate the adductors. Strengthening your hip adductors will tighten your inner thigh area, and might also help you prevent knee injuries and pain, since these muscles stabilize the pelvis and knee during activities like running or biking.
There are some arguments against using the hip adduction machine, One of the biggest problems is that the movements you perform on it are not movements you would perform in real life. While the machines work these muscles in isolation, the adductors and abductors are actually meant to work in coordination with the rest of the body to stabilize the legs.
How to do
Adjust seat width so that you feel a slight stretch on your adductor muscles when your inner thighs are placed on the pads.
Sit tall with proper posture and a straight back, Place feet on foot level or platform.
Slowly squeeze your thighs together, Keep feet straight and pointed forward. at the end hold the squeeze for a moment.
Then slowly release the squeeze returning to the starting leg position, and repeat.