LinkedIn won't give you bold or italic, so this does. Select text, pick a style, and the formatting survives pasting anywhere. Free, and you don't need an account.
LinkedIn strips real formatting from posts. No built-in bold, no italic, nothing. So formatters cheat: they swap your letters for Unicode look-alikes from the Mathematical Alphanumeric Symbols block, characters that just happen to look like styled A-Z. And since they're ordinary characters as far as any app cares, they survive copy-paste into LinkedIn, X, Instagram bios, wherever you take them.
Screen readers announce these characters awkwardly (a styled A reads as "mathematical bold capital A"), and search can't match styled words. Style a hook or a key phrase for emphasis rather than formatting entire posts. The clear-formatting button converts styled text back to plain letters.