The feature is called LinkedIn Lead Gen Forms, and it’s aim is to “drive even more high-quality leads from your Sponsored Content campaigns by removing the main barrier to mobile conversion: making someone complete a clunky contact form on a smartphone.”
It works like this: When a LinkedIn user clicks on your sponsored content, they’re presented with a pre-populated form that they can easily submit. This eliminates the need to fill out a form with all of their contact information.
Then, according to the platform, the information is sent to you:
Once someone submits a Lead Gen Form, you’ll get a comprehensive lead record that can include that person’s name and contact info, company name, seniority, job title, location, and more.