How to save a file for Realm Database in React Native

hello everyone, I work on a react native project. I try to save all APİ request in Realm DB. because this application should be usable even when there is no internet connection. Users can upload documents. I must save the document with the necessary parameters for the request .I try to save this document in Realm like a object but this is causing problems when sending requests because my service waiting a file for document upload.

my questions is here
1-) how to save a file(like image, video etc.) in realm db for react native?
2-)do you have any idea this offline app? how I can code structure?

thank you