The iHealth Lite (HS4S) scale can track an unlimited number of users.
Each user of the scale must have an iHealth account.
To add a new user, follow the installation procedure for your model of smartphone (except the first step).
Installation of the iHealth Lite (HS4S) scale from an iOS (Apple) device.
Installation of the iHealth Lite (HS4S) scale from an Android smartphone.
*credit to Sylvain of iHealth Labs EU
https://helpcenter.ihealthlabs.eu/hc/en-gb/articles/360000006889-iHealth-Lite-HS4S-How-to-add-a-new-user