Clear cell phone info?

how do I delete the info from my old cellphone soI can give it to someone else to use. Its an old samsung sph a6660Clear cell phone info?
thier must be some option called restore factory settings, just use it.Clear cell phone info?
go to menu setting .factory reset... password should be 000000
1 Main menu


2 Settings


3 Security


4 Type IN Unlock code(defalt is last 4 digets of cell#)


5 Reset Default

Do puppies lose their