if my phone is backed up on i cloud can i reset the phone to factory settings and down load to new phone from cloud as i dont have pc/laptop/or tablet

You can back up to the cloud and reset and restore onto a different device, but you might not get all of the content copied over e.g. if you previously had a computer and synced your own music to the phone's Music app (and/or own videos in the TV app and/or photos to the Photos app) it won't be stored in the backup and therefore won't be copied onto a new device.

About backups and restores : About backups for iOS devices - Apple Support