Where fancy text works on Discord
Fancy letters work in your display name, server nicknames, About Me bio, and server and channel names. Your username, the unique handle, only accepts lowercase letters, numbers, underscores and periods, so keep that plain.
For messages, try Discordโs own formatting
In chat, Discord already formats text for you: **bold**, *italic*, __underline__, ~~strikethrough~~, `code` and ||spoiler||. It reads better and works with screen readers, so save fancy fonts for names and bios.