Types of mountain bikes
Hardtails are bikes that dont have back suspension but do have front suspension.The front suspension is called a fork and the amount it compresses is called travel, The typical amount of travel on hardtail is between 120-150mm. They also are better for beginer mountain bikers becuase they are less expensive and easier to take care of.
Full suspension bikes are bikes that have both front and back suyspension on the bike. They are usually bought by people who ar emore into the sport and want to get better at what they are doing whether it be jumps, races or just getting more confident on the trails