You can join friends in Minecraft via Realms or by playing together on a dedicated Minecraft server. In Bedrock, you can also ...

Add-ons are exclusive to the Bedrock edition and can be compared to mods that exist within the Java Edition of Minecraft ... it's now time to add them to the realm. To do this, players must ...

but some that change the nature of the game a lot will require you to make a new Realm or World. World packs, like Aquatic Life, will require making a new World for that add-on. Java Edition users ...