Hello @Niren Adhikary (NAD) , you need to review the B2C audit logs. You will get information such as application id, user flow used, local or federated user id, CA results and more. Here's a sample query using MS Graph:
https://graph.microsoft.com/v1.0/auditLogs/directoryAudits?$filter=loggedByService eq 'B2C'
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