Question is unclear. Do you want to store the file itself, or just the contents?
If you want to store the file you need a LOB
] type, more specifically a BLOB. An alternative in keeping the file, but not uploading to the database is saving the file in a DMS (document management system) and saving the link to the location.
If you want to save the rtf text you can do so via richtextbox, although I don't know how it will react on complex documents (headers, tables, images, ...).
The link has a sample in ADO.Net, but any other provider will have something similar.
Read it through, if you have more specific questions, update this question with more info.
Hope this helps.