Analyze Your iCloud Storage
Finding out what is on your iCloud storage should be your first step. Visit your iPhone's Settings to do this. Click to open the iCloud icon there after tapping the Apple ID name at the top of the screen. Next, select Manage Storage.
Simply tap the name of the device whose backup you'd like to remove in order to delete previous iPhone backups stored in iCloud. Select Delete Backup > turn off and delete after that. Instead of using iCloud, you can use iTunes to back up the data on your iPhone to your PC.
If you're unsure if you want to disable access to your iCloud photo library, go to Photos and clear out the unnecessary files. Remove each and every duplicate as well as any problematic photos or videos. Make sure to delete them from the Recently deleted album to free up space after you've done that.
Along with the Photo Library, Apple also backs up the data from particular apps to iCloud. This includes the information from the games and applications you have downloaded on your smartphone. Although it might not seem like a problem at first, the apps could use up a significant amount of the available iCloud storage.
Similar to Google Drive, Apple may keep all of your information in your iCloud Drive, which includes documents, files generated by apps, communications, and many other types of data. The information could build up over time and use a significant quantity of storage space.