What is iCloud storage?
When you sign up for iCloud, you automatically get 1 GB of free storage. You can access content stored in iCloud on iCloud.com.
You can check how much iCloud storage you have available. To upgrade your storage, you need to sign in with your Apple ID on an iPhone, iPad, iPod touch or Mac. See Get more iCloud features and the Apple Support article Web-only access to iCloud.
If your iCloud storage runs low, you can delete files in iCloud Drive to increase your available space.