What SSD can I ad to my Desktop?

I have a Lenovo, 1TB Hybrid Hard Drive and 8GB ram.
I'm new to computers and I like to play games so I want to know if I can add an SSD to my pc and if I can witch one does any kind work? Can anyone tell me.

Any one should work.

Yes you can might have to buy a ssd caddy to hold the ssd in place the samsung 850 evo 120 gb for 62 dollars is a reliable one

You can put any SSD of any brand or size in the machine. I would only go for good, known brands like Intel, Samsung, Crucial, or OCZ who are known for making good memory chips. You most likely will need a 2.5" to 3.5" caddy so that you will be able to properly install it in your case.