why federated user created in Azure AD B2C tenant on Sign up Custom policy

Question

I Have Federated tenant, when i am sign with federated emailid, it will create user with federated email, but this is not a correct senario, because when user is federated user we can't insert him in our tenant. That is extra burden to Tenant

let me know any solution for this

Thanks & Regards,
varaprasad
varaprasad.mcd@harsh.com .com