Thanks @piyush_khandelwal. Want to know one more thing that why using sendEmail attribute in the Before Provisioning Rule will work and why using the sendEmail attribute on the Create Profile throws the error:
Error[“sailpoint.connector.InvalidRequestException: [ InvalidRequestException ] \n [ Error details ] Request execution failed. HTTP Error code : 400, Okta Error code : E0000001, errorSummary : Api validation failed: newUser, errorCauses:[{errorSummary\u003dProperty name \u0027sendEmail\u0027 is not defined in profile}].”]