How to add a line break on LinkedIn
Write the post on the left with one idea per line and blank lines between paragraphs. Copy the version on the right and paste it into LinkedIn. Each empty line holds an invisible character so LinkedIn keeps it.
For bold text and bullet lists as well as spacing, use the LinkedIn Post Formatter.
Line breaks in LinkedIn messages
In LinkedIn messages, pressing Enter may send the message, depending on your settings. Shift + Enter adds a new line. You can also write the message here, copy it, and paste it in with the spacing intact.