I know this question has been answered before but can't find it.
I am such a newbie at this. What does it mean to jailbreak a phone and why would I want to do it?
Then, a browse through the Jailbreaking section of this forum will show many reason "why jailbreak" - from tweaks to make the phone work the way you want all the way to themes to make you phone unique.
There's a lot there, so grab a snack, a beverage of your choice and ... happy reading!