Discord supports two different text styling approaches, and knowing which applies where saves a lot of frustration.
Markdown: messages only
Inside a message in any channel or DM, Discord parses simple Markdown: **bold** becomes bold, *italic* becomes italic, __underline__ underlines, ~~strike~~ strikes through, backticks wrap code, and ||spoiler|| creates a spoiler tag. This rendering is handled by Discord’s client. It works only in message bodies — not in your display name, not in channel names, not in role names.
Unicode: everywhere text is accepted
Unicode character substitution (what this site and all "fancy text" tools produce) works anywhere Discord accepts text input. That includes server names, channel names, role names, category names, display names, status text, forum post titles, and thread names — the places Markdown can’t reach. The tradeoff: Unicode styling is less readable at a glance, so use it where visual identity matters more than quick scanning.
Which to use when
For emphasis inside a sentence you’re writing, Markdown is cleaner and faster. For branding a server, making role tags stand out, or giving yourself a recognizable display name, Unicode is the only option.