Synchronization is done automatically by the scale itself after the measurement.
To check the details of your measurement go in Menu > Weight > List and select the measure you want to check
Note - Synchronization is possible only if the scale is connected to internet. Otherwise, the measurement is saved in memory and will be synchronized as soon as the connection is restored.
If you encounter a synchronization problem, please see the article My measurement results is not syncing to the App/Cloud
If you encounter a synchronization problem, please see the article My measurement results is not syncing to the App/Cloud
*credit to Sylvain of iHealth Labs EU
https://helpcenter.ihealthlabs.eu/hc/en-gb/articles/211439949-iHealth-Core-HS6-How-to-sync-measurements