Jailbreaking is process changing the iPhone (or iPad) software to remove the restrictions and limitations imposed by Apple. The principal limitation is that software can only be installed from the App Store. After jailbroking iphone you can install software from a rival to App Store, and also manually using files downloaded from internet.

Advantages:
*You can explore the File-System with the iFile.
*You can free up space with the iCleaner.
*You can have beautiful page transitions with the Barrel.
*You can put Biometric protection on almost any folder/ any app using the BioProtect.
*You can add too many shortcuts like enabling the Mobile Data, turning on the Location Services,   enabling the Personal Hotspot in my Control Centre with the CCSettings.
*You can Install Apps Outside App Store. Jailbreak will Allow you to Install Apps from Third Party Sites
*You can Customize Iphone Themes. Jailbreak Allow you to Download and Customize Themes and Apprearance of iOs
Disadvantages:
*Security-jailbroken iPhones are no longer in Apple’s Protection, you run the risk of opening your iPhone up to malware apps.
*Stability-Since most apps don’t go through the rigorous testing process that Apple puts apps through, downloading an unapproved app and running it could affect the stability of your phone.
*Latest iOs updates-After JailBrake you cant get iOs Updates from Apple, you have to wait for Jailbroken version to be released.
*Battery Life-Since jailbreaking unlocks many features that would otherwise be unavailable to you, some apps may be accessing services that could really suck up battery life on your iOS device.
*Warranty-jailbreaking your iPhone will void your warranty with Apple.