Refactoring existing annual leave managment web application

I have created a React JS application with a firebase backend application and I need to Refactor it and add multiple features to it and also document it.

The website will allow a user to manage his annual leaves with his team.

The appliactoin it’s farily simple and not complicated.

I need to do the following:

– Refactor it and make sure that it’s reliable.
– Add multiple features.
– Document it.
– Fix all issues.