Lansweeper can only pull data from devices if they have one or more of the following protocols enabled: FTP, HTTP, HTTPS, JetDirect, SIP, SMTP, SNMP (SNMPv1, SNMPv2 or SNMPv3), SSH, Telnet or WMI. As far as we know, iOS devices don't have any of these protocols available, which makes it impossible for Lansweeper to pull data from them.
You can
tick Save Pinged IP for your IP ranges to have asset pages generated for all pingable IPs, but no data will be available if none of the aforementioned protocols are enabled.