Creating Users in SAP NetWeaver Voice 
SAP NetWeaver Voice uses the following users:
Voice application developer
Voice application developer develops voice applications and requires the same authorizations and permissions as developers of the other NetWeaver applications.
You use the Identity Management component of the SAP NetWeaver AS Java to create and maintain users, groups and roles.
Runtime service user
SAP NetWeaver Voice creates the service user voice_rt_service by default. Voice Data Runtime uses this runtime service user to access destinations or Web services that have been configured in the SAP NetWeaver AS Java using the NetWeaver Administrator.
The user voice_rt_service has the administrator role by default, but you can override this manually using the Identity Management of the user management engine.
More information: Administration of Users and Roles