How to make text bold on Facebook
Facebook does not have a bold button for regular posts or comments. Write your text here, select the words you want to emphasise, and press B for bold or I for italic. Then copy the post and paste it into Facebook.
The styled words are Unicode characters, so they keep their look in posts, comments, page updates, and Messenger.
When to use bold and italic on Facebook
Bold works well for a headline at the top of a long post, an offer, a date, or the call to action. Italic suits quotes and names of books or shows. Styling a whole post makes it harder to read, so pick a few words.