What happens when I delete backup on iPhone 6?

When you delete a backup on your iphone 6, the stored data and settings from that backup are permanently removed from iCloud or your computer, depending on where the backup was saved. This means you will no longer be able to restore your iphone to that specific state if needed in the future. However, this action does not affect the current data on your iphone; it only removes the backup file. Always ensure you have the necessary data saved elsewhere before deleting a backup.