How to Format Text on Every Platform: The Definitive Cross-Platform Reference

Not in posts or comments. LinkedIn's main composer — the box for feed posts, comments, and your headline — is plain text with no bold or italic button and no markdown parsing, so typing `*bold*` just leaves the asterisks visible. The only way to show bold or italic there is to paste Unicode styled characters (𝗯𝗼𝗹𝗱, 𝘪𝘵𝘢𝘭𝘪𝘤) generated by a converter; the style is baked into the characters themselves, so it survives the paste into a plain-text field. The one real exception is LinkedIn's 'Write article' editor, which is a genuine rich-text editor with working bold, italic, headings, quotes, and lists. Important caveat: Unicode text in posts is not read by LinkedIn's search and is announced poorly by screen readers, so keep it to a short headline or one emphasized phrase — never style keywords, names, or hashtags you want found or read aloud.

Because WhatsApp natively parses that markup and Instagram doesn't. WhatsApp reads `*text*` as a formatting instruction and renders it bold — it also does `_italic_`, `~strikethrough~`, and triple-backtick monospace — hiding the symbols on display. Instagram's caption, bio, and comment fields are plain text with no formatting engine at all, so it keeps every asterisk as a literal character: `*hello*` stays `*hello*`. To get bold or italic on Instagram you can't use markup; you have to paste Unicode styled characters (𝗯𝗼𝗹𝗱, 𝘪𝘵𝘢𝘭𝘪𝘤) where the style is part of the letter itself. This same split explains most cross-app confusion: chat apps like WhatsApp, Telegram, and Discord parse typed symbols, while public feeds like Instagram, X/Twitter, Threads, TikTok, and Facebook are plain-text boxes that need the Unicode workaround.

The two apps simply chose different native syntaxes. Slack uses single asterisks — `*bold*` — plus `_italic_`, `~strikethrough~`, and backticks for `code`; typing `**bold**` in Slack shows literal asterisks or leaves an extra one inside the bold. Discord follows standard Markdown with double asterisks — `**bold**` — plus `*italic*`, `__underline__`, `~~strikethrough~~`, and backticks for `code`. Slack also offers a WYSIWYG toolbar (the Aa icon) so you can select text and click B instead of typing symbols, while Discord renders its markdown live as you type. Mixing the two conventions — using Discord's `**bold**` in Slack, or Slack's `*bold*` expecting Discord — is the single most common cross-platform formatting mistake, so check whether the app wants one symbol or two before you post.

YouTube has limited but real native markup that works in both comments and video descriptions. Wrap text in asterisks for `*bold*`, underscores for `_italic_`, and hyphens for `-strikethrough-`; the symbols are hidden and the styling renders for everyone. Two gotchas decide whether it works. First, put a space (or line start) between the formatted text and any adjacent punctuation — markup touching a comma or period often fails to render. Second, strikethrough won't work around numerals: `-2024-` reads the hyphen as a minus sign, so it stays literal. There is no native bullet list, inline code, or heading formatting on YouTube, so for those you'd type a • character manually or paste Unicode styled characters. For a standout line or channel flourish the native markup is enough; reserve pasted Unicode for emphasis the markup can't produce.

It can be, so use it sparingly and deliberately. Unicode styled letters (𝗯𝗼𝗹𝗱, 𝘪𝘵𝘢𝘭𝘪𝘤, 𝓼𝓬𝓻𝓲𝓹𝓽) are distinct code points from normal letters — a Unicode bold 'A' is a different character than a regular 'A'. That substitution is exactly why screen readers often read these strings as gibberish, skip them, or announce each symbol by its formal name ('mathematical bold small a'), which is a real barrier for visually impaired readers. The same swap can break hashtag matching, in-app search, and how usernames are indexed, because the platform no longer sees ordinary letters. The safe rule: use Unicode for short emphasis only — a standout display name, one punchy line, a profile flourish — and never for body copy, calls-to-action, links, or anything that must be searched, clicked, or read aloud. Where a platform offers native formatting, prefer it; native text stays accessible and searchable.

Native formatting (a toolbar or markup the app actually parses): WhatsApp, Telegram, Discord, Slack, Reddit, YouTube comments and descriptions, and LinkedIn's 'Write article' editor. In these you type symbols like `*bold*` or click a B button and the app renders genuine styled text that stays accessible and searchable. Unicode workaround (plain-text boxes with no formatting feature at all): Instagram, X/Twitter, Threads, TikTok, Facebook, and LinkedIn's posts and comments. In these the only way to show bold or italic is to paste Unicode styled characters whose style is baked into the letter. The rule of thumb: chat and community apps tend to format natively, while public social feeds tend to be plain text where pasted Unicode is your only option. When an app is native, always prefer it — it renders consistently, survives in-app search, and is read correctly by assistive technology.