The VIP subscription is a membership you can get in the game's store. It allows you to play without ads, gives you endless lives and gives you the chance to get special discounts and packs.
You can subscribe in the App Store or in the Google Play Store, depending on the device you use. Please visit the following articles if you need information on how to cancel it: How to cancel my VIP subscription if I use iOS? - How to cancel my VIP subscription if I use Android?
Bear in mind that you can get the subscription for a month, three months or a year (this last option will grant you extra benefits).