"Minecraft Realms" doesn't support mods. How to make your own 'Minecraft: Java Edition' multiplayer server, or join a friend's Servers are the basic building block of "Minecraft's" multiplayer mode.

Realms are also an option for Minecraft PE, Bedrock, and Java players to join their friends. This must occur through an invite; if the host doesn't request the player to join, it's not available.

In Minecraft Java Edition, players can either jump into a world on their own and explore it, or they can join their friends in a multiplayer world and play together.