You wonder how others format their text on LinkedIn, while the LinkedIn GUI does not permit it ?
This is one of the many solutions, online, free.
It allows to add emojis (as LinkedIn), but also bold, underlines, italic and so on.
Tip #1: do not publish directly the formatted text. Copy/past into you own LinkedIn to have more control and a last verification.
Tip #2: do not store into an intermediary format (like a text file) as you may loose part of the formatting
Free, No Download/Install required, No registration