Firstly, if you are a kid
, and you know your parent has set up some family controls on your Minecraft game or on your Xbox, you need to get them to read the section at the bottom of this article to help you.
Cross-play allows you to play Minecraft with friends who own the game on a different platform to you, however, to access it, you need a Microsoft account to sign in to Xbox Live. In fact, you'll need a Microsoft account to access all online features in Minecraft. This includes platforms like the PS4 and the Nintendo Switch — which are not owned by Microsoft. The main platforms that currently, support cross-platform play are Xbox One, PS4, Nintendo Switch, Windows 10, iOS and Android.
A Microsoft account isn't necessarily needed to play Minecraft. You can still play the game offline, but to play online, you're going to need one. You'll also need one to join your friends, host realms or join public servers. Having a Microsoft account also allows you to purchase Minecraft Coins and items such as skins from the Minecraft Marketplace. Items purchased and your coins will also be linked to that Microsoft account, so if you decide to log in on another device later on down the line, you'll still have access to all of your gear and currency. You'll also be able to earn Xbox Live Achievements with a Microsoft account, except on the PS4 version, where any progress made count towards the PlayStation Trophy system.
To sign up for a free Microsoft account follow the link here