Command blocks are one of those items that delve into super-nerd territory. So how does one go about getting it? The good news is that you’ll be able to go about securing them the same way, whether you’re playing Bedrock or Java editions of the title.
First: You’ll want to make sure that you’re playing in Creative Mode, and that you’ve got cheats enabled. Head over to your Realms server and toggle those on.
Source: https://www.distractify.com/p/how-to-get-a-command-block-minecraft