Hi @gauravd85673172,
Depends on the type of profile merge rule you're looking to implement. If you are looking to qualify customer IDs alongside device IDs into segments, you'll want to make sure the ID sync is in place to stitch those customer IDs and device IDs together.
I would recommend looking into our documentation for the Experience Cloud Identity Service, or also known as the Visitor ID service for our "setCustomerIDs" method.
https://docs.adobe.com/content/help/en/id-service/using/id-service-api/methods/setcustomerids.html
Note: In this documentation it uses "userid". This needs to be changed to match the integration code on your AAM data source the customer IDs will be linked with.
Regards,
Shane
