EA and BioWare have announced that the first closed alpha test for Anthem will take place on December 8th and December 9th. The event is designed for players to help developers "adjust things like matchmaking" and that players need to be aware that changes, such as server load, may occur "on the fly". As a result the alpha event is "more limited than what we want to share in the pre-launch demos".
Interested players on PC, PlayStation 4 and XBox One can sign up to be part of the EA Community Playtest program. Each potential tester can only register for the program on one platform. Additionally, closed alpha is not part of the pre-order program or through EA Access / Origin Access programs. It requires a separate registration.
Learn more about the Anthem alpha experience, including detailed instructions on how to register.