How to add a missing movie on BetaSeries?

You can use this form to suggest a movie that isn't already on BetaSeries: https://www.betaseries.com/films/ajouter

It is accessible from the Movies > Suggest a movie menu.

It will then be added automatically to BetaSeries.

If you can't find the movie through this form, you can sign up and add the movie on TheMovieDB, which is a collaborative site, then suggest it again on BetaSeries.