If you want to download movies to phone for watching offline, I suggest you use a movie downloader to download movie to computer at first, then transfer them from computer to your iPhone or Android phone. I have ever try an all-in-one movie downloader, it called TunesBank iMovieTool, which is a helpful streaming video downloader, which supports to download movies from OTT sites such as Netflix, Apple TV+, Amazon Prime, Disney+, HBO Max, and Hulu. I have use this tool to download Netflix movie to computer and save it as MP4 format. Now, I am able to offline viewing movies on Android phone.