https://www.cnet.com/news/get-3-free-movies-from-movies-anywhere/

Movies Anywhere is designed to merge your Apple iTunes, FandangoNow, Google Play, Microsoft Movies & TV, Prime Video and Vudu movie libraries.

Once you sync those services, nearly every movie you own should be accessible across all of them. In other words, you'll find iTunes purchases in your Google Play account, Prime purchases in your Vudu account and so on.