I own a Discord guild and would like to add custom emoji like other guild have done.
In the below screenshot, it shows some indicator emoji that I cannot type, such as
In your guild settings panel, granted you have the Manage Emojis permission (you are the guild owner so you have all permissions), you will have a tab named "Emoji".
From there you can upload, rename, or remove custom emoji for that guild.
Here is how you can do those things:
Remember, you can only have 50 emoji in a single guild.