If you pay for Google Drive storage, there are some changes rolling out that you need to be aware of going forward. From now on your Drive subscription will be managed within the Google Play Store like your other subscription apps. Gone will be the separate purchasing and process for adding storage to your account. Instead, for Android users, it will all roll up into the Play Store where you can manage all of your subscriptions (like Google Play Music) from one place.
The new process won’t effect anything you have to do as an end user. Google is migrating accounts to Google Play Store and you should have received an email on this in December. Once your account is converted over, you will see it as part of your subscriptions in the store.