Is it possible to fine tune then use it to query a specific documents or files to get the contextual information?
In general, it is not necessary to use “fine tune” to query a specific document or set of documents. This can be done by using either search, or embeddings.
If the corpus doesn’t change too often, it is more economically viable to fetch and store the embeddings.
Have you looked at the answers API OpenAI API? Do you have a particular task you want to use fine-tuning for, or do you just want to support general queries?