Below is a video that should be watched to get all information and see it first hand how it works.
Within this article and video below we cover social share incentives and social meta date or social media information that gets displayed on facebook or twitter when a share button is clicked.
#1 click on thank you page tab, #2 click on social share incentives for attendees #3 turn on the social share incentives to display the social share icons. #4 if you want to incentivise them you can provide a Video or a PDF, #5 Now click on advanced options to add in your data
#2 click on social meta tag settings #3 and #4 you can add in your title and description and image you want to display within facebook or twitter under the social meta options within the advanced options tab..
After you add in the social meta data into your EW event and save and publish it copy your registration url from publishing options and go to https://developers.facebook.com/tools/debug/ and paste in that reg url into it and click debug
If it has not been shared on FB before you will click on fetch new information
once it gets the data it may or may not be what you added into EW and it may take some time for the servers to propagate the correct info. You can click on scrape again or re scrape as often as you wish until it displays the correct info
For Twitter you can go and do same thing here https://cards-dev.twitter.com/validator and click on preview card button. if it does not show keep clicking on preview card to re load.. again it may take time but it will force it through eventually