Open Settings on your iPhone or iPad
Tap your name
Tap iCloud
Tap Manage Account Storage or Manage Storage
Review what is using space
Delete old backups you no longer need
Turn off backup for apps you do not want stored in iCloud
Delete photos and videos you no longer need from iCloud Photos
Empty the Recently Deleted album in Photos
Delete large files from iCloud Drive
Remove old documents from the Files app
Delete messages and attachments stored in iCloud
Remove old voice memos
Delete unused app data stored in iCloud
Clear Safari data if it is synced to iCloud
Check Mail attachments and delete large emails if needed
Reduce the size of future backups
Sign in to iCloud.com and delete files there if easier
Wait for storage changes to sync across devices