There is not technically a way to directly input social sharing on your landing page. Our social sharing options are on the "thank you page" so your users can share after they've signed up.
However, you can do this by inputting social icons as images and linking them to your social media. You can add a new block where you can upload icon images of social media sites.
See an example below
Choose Link to External URL and put your social media URL.
Trust you find this helpful.