With Playfab, users can register an account, securely storing account details like usernames and email addresses in its database, allowing players to easily log back in and pick up where they left off. This system will also prove invaluable for future features, such as character customisation, as players will be able to create and save their own unique characters. 

Why Playfab?

I chose the Playfab as it's easy to set up and use with Unity. It provides tools for player authentication and leaderboard management.