is it possible to go and install a suspension onto a bike that dosen't have any suspension? I have a huffy 3.0 fortress mountain bike, I have to ride on some bumpy roads and trails, I have a friend who has a bike that has suspension. I rode it once and it was very smooth when I went over a speed bump. So I wondered if it was possible to install a suspension onto my bike. I tried to search it up, but I didn't find anything helpful. So I decided to see if any of you can answer that.
You could add a suspension fork (this bike seems to come with a very low quality one) or suspension seatpost or suspension stem. 

On such a low end bike though, only the suspension seatpost would make sense -- for the other options, you're more likely better off getting a new bike.

Another option is to get the biggest tires that fit and run them at a low pressure, which should provide some shock absorption. But this bike wasn't intended for use off-road really -- just to be ridden a few miles on road.