The first thing you need to find out is what IOS you have on your current device. Depending on the OS your iPad/iPhone/etc. is running, you will have to find a jailbreak application that is made for your OS.
Note: Jailbreaking does void any security measures that Apple has implemented. So be careful of what you do with your device after the matter. Also, make sure to make a full backup of your device before you begin. If an error occurs, a multitude of issues could arise. Most of them can be fixed with the backup you made prior to. And as always, make sure to research and make sure you know what your doing. These programs DO NOT hold responsibility for anything that happens to your device. If you have any more questions or want more in depth answers, Feel free to PM me anytime, and I will get back to you.