Lansweeper can scan devices that have one of the protocols listed in
this article available. Both Android and iOS devices are pretty locked down unfortunately and can't be contacted through any of these protocols. The Android devices that have been scanned in your environment were likely within the same subnet as your scanning server itself. Due to this the MAC address of these devices will have been retrieved from the ARP table of your Lansweeper server. An IP address and MAC address are enough to automatically generate an asset page. For now, the only way to pick up these devices if outside of your Lansweeper server's subnet would be to go to Scanning\Scanning Target and checking the Save Pinged IP option for the IP Range scanning target that covers these devices. This will generate a basic asset page that can be manually completed.
Scanning both iOS and Android devices is something that's already on our wishlist, though this isn't yet in active development. It would likely require some kind of scanning app to be installed on the devices. I've moved this topic to the wishlist section of our forums in this context. At this moment we don't have an estimated release date for this feature.