Redirects using create react app

As mentioned in the File based configuration documentation, a netlify.toml file should go at the root of the repository. A _redirects file as mentioned in the Static routing overview goes in the publish directory—which in the case of React means putting it in the public directory.

For an SPA like React, especially if using React Router, you will generally want a single rule as outlined in [Support Guide] Direct links to my single page app (SPA) don't work
netlify.toml

[redirects]
  from = "/*"
  to = "/index.html"
  status = 200

_redirects

/*    /index.html    200