Both you and her have to do two separate applications and two individual bank accounts. Dependants require a marriage certificate. Only then can you sponsor her using your bank account (in some embassies)
The ask:thailand community, consisting of multiple Q/A groups with over 100,000 members, powers this platform. It is not an official government resource. Our members actively contribute to this resource, and while we strive for accuracy, we cannot guarantee its complete reliability. Assistance to travelers is provided as a community service.