Hello,
Moodle 3.3 new features say that is has emoji support;
https://docs.moodle.org/33/en/New_features
But from where do you add these emojis to your Moodle? Do you have to copy/paste them somewhere? Which settings are required in Moodle?
By emoji support, it means if you add emoji into any text - it'll work. So this is mostly mobile users though you can do this on Windows and OS X by using the text inputs in the OS.
Your other option for adding emoji is to use a browser plugin that lets you select emojis to add into text.
AFAIK - There isn't any functionality to convert typical ASCII emoticons in to Emoji built in to Moodle... maybe someone can develop that as a plugin!
Important: EmojiOne changed the licensing of their emojis between version 2.2.7 (CC-by-sa) and version 3.x. Which version is in Moodle 3.3? I hope it is version 2.2.7