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
Web Applications Stack Exchange is a question and answer site for power users of web applications. It only takes a minute to sign up.Sign up to join this community
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.