If you want to experience the "Fusion" mechanics first-hand, there are several mobile and console options: Internet Archive
This is currently the most reliable way to watch the series legally. In many regions, including the United States, you can stream both dubbed and subbed versions. With a Crunchyroll Mega Fan subscription, you can download episodes for offline viewing on mobile devices. download digimon fusion
For those looking for historical preservation of the English dubs (Saban Entertainment versions), some collections are available for free download and streaming via the Internet Archive . Digimon Fusion Video Games If you want to experience the "Fusion" mechanics
Below is a comprehensive guide on where you can legally download and stream Digimon Fusion content. Where to Download and Stream Digimon Fusion Anime including the United States