Front shock Absorbers
What information is available on these models make it appears to be an lower cost Big Box Store quality bike. It has non descript components. These bikes typically have a very simple suspension. The shocks consist of a spring and plastic sleeves that act as bushings. The dampening rate can be adjusted by removing the plastic caps on the fork crown and inserting a long 5mm allen wrench. Tightening the screws preloads the springs and makes it stiffer. There is no rebound adjustment. Parts to rebuild these are usually not available. You can (with care) disassemble them to clean and lube the plastic sleeves. If this doesn't improve anything, a new fork will likely cost more than replacement cost of the whole bike. These types of bikes can be used as short term commuters, they won't last long if used for aggressive off road riding.