The procedure of jailbreaking your iOS 9.3.3 device, which means removing the restrictions set by Apple for the operating system that your iPhone, iPad or iPod uses is done using the internet, finding a secure, trusted location from which to download the jailbreak software from, and then loading the jailbreak application on your device through an USB cable.
By jailbreaking your iPhone, for example, you will have the ability not only to get apps, updates etc from the Apple App Store, make phone calls like always, use services like iTunes – but you will also be able to get a ton of interesting stuff from Cydia download iOS 9.3.3, otherwise not available without first doing the jailbreak.
Other than the already mentioned iOS 9.2 or 9.3.3 driven devices, jailbreaking also works for Apple TVs. After the jailbreak, you will be able to access a plethora of additional extensions, themes, applications etc. that aren’t otherwise accessible in the App Store by Apple. The process itself is being performed by jailbreaking the operating system’s (iOS) root access.
A device ran by the iOS operating system can be restored in iTunes or by doing an update to the current iOS version. To solve this, you will either have to reload the jailbreak again or use a partial iOS update by doing a Semi-Restore.
Proper updates for your jailbreak are needed for each iOS version or update, because for each Apple iOS update, a new jailbreak will be needed to fit that particular version.
The Apple App Store can accept or deny certain applications from being displayed in the Apple App Store for different reasons (for example, they already have a similar app). By jailbreaking your device and having access to the Cydia App Store, you can get apps that aren’t available on the Apple App Store.
However, due to security reasons, it’s recommended that you backup your files if you decide to install an app from the Cydia App Store because there is no guarantee that the app works properly or that it isn’t harmful for your device. Reading through the reviews for that particular app is a good idea and will help preventing you from crashing or damaging your device.