Most mountain bikes have at least front suspension, also known as a
Full suspension mountain bikes have more bounce out the back with a rear shock. Budget will likely dictate whether you can afford to splash out on a full-sus bike as they come at a higher price point.
Hardtails are a brilliant option for beginners because of their lower maintenance, high affordability and lighter weight construction. You may think you’ll be at a disadvantage without rear suspension, but hardtails can tackle all but the gnarliest terrain and, if you’re just starting out, you’ll want to stay well clear of anything too sketchy anyway. That said, if you do find yourself a little out of your depth, the simplicity of a hardtail mountain bike will teach you a lot about how to ride properly.
If you decide further down the road that you want to upgrade to a full-suspension mountain bike or an e-mtb, you can still keep hold of your hardtail for commuting or lending to a friend.