In case you are looking for the answer “Can I actually bold text in a LinkedIn post”, unfortunately, the answer here would be: “Generally, no.” Normal posts on LinkedIn do not allow its users to highlight or bold text within the copy, however, you may implement bolded text in your articles that are part of your LinkedIn Newsletters.
Source: BookMark
Some general rules for bolding text say that you should do this when you want to point out something important – a piece of information, some data, statistics, hyperlinks, or just an important sentence or quote, part of the text. This will increase the chance that your audience will definitely read the highlighted information.