There is, but it works a little different in Sims 4. In Sims 4 you can give whatever title to your self-employed sim, and is not required on any set type of skills.
https://simsvip.com/2018/10/22/the-sims-4-self-employed-tutorial-update-ui-changes-more-november-game-patch/
Self-Employment – Vixella has confirmed in her overview video that the patch will add the ability for Sims to register a custom careers, aka: self-employment. The way it works is Sims will select the new “Register with Ministry of Labor” interaction on their cell phone, & fill in the blanks on the pop up that appears. There are no specific skills or actions tied to these careers, but it does allow your Sims to “freelance” and not be labeled unemployed.
https://simsvip.com/wp-content/uploads/2018/10/uuu.png