Back up from previous backup

Settings>Your Name>iCloud>iCloud Backup. That will show you the date of your last backup. ICloud only stores one backup per device. Each subsequent backup overwrites the previous backup. If you have multiple iOS devices backing up to iCloud, go to Settings>Your Name>iCloud>Manage Storage>Backups. You can tap on a device Name in there to see the time and date of the last backup for your other devices.