Photoshop is actually a computer progam that allows you to manipulate images. There are other programs that do the same thing but usually people still call it photoshopping.
They can be complicated for beginners, if you are interested have a look and see if there are any nightclasses/workshops near you.
It is possible to download basic packages from the internet, but if you don't now how to use them it might just be more frustrating for you. I'm trying to learn myself at the moment!