Add features to a file converter app

I need a react dev to add some features to my file converter app. The app is already completed, however, I want someone to add more file types available for conversion. Currently, the app only supports images and PDFs, but I want someone to add support for different types. I'm flexible on which files as long as it's not multimedia (videos, music, or images). Whatever is easiest, some examples include documents (word doc, presentations) or even code. The app is made with Electron but you don't directly need it (though it could help). Keep in mind that the budget I have posted is what I will pay. We can't negotiate once the project has started.