Does ChatGBT have Trainable Models


Google have Bard to compete with ChatGPT, also they have service that provide trouble models, does ChatGBT have such service ? now its sort of confusing for me as Bard should be the already trained model but just wanted to see OpenAI perspective and business model, is this trainable models confusing ? in there plans ? and ChatGPT is enough ?

Kindest Regards