It is very easy to share engagement questions on social media. Doing so is a great way to drive traffic from your social media to your poll question.
Simply go to the page where your poll is posted and click on the kebab menu (the three dots at the upper right). A menu will slide out. Share is the last menu item.
When you click on Share, a field will open showing you the link to share manually and three icons that will allow you to post the link to Twitter, Facebook, or LinkedIn.
This video goes over the process.