There are two different places where you'll find the option to share your posts to social media:
On the post page Immediately after you publish your post you’ll be taken to that post’s page, and you’ll have the option to share your post on your Facebook and Twitter accounts(requires log in authentication).
Directly from the post in your Feed You can share posts directly from your creator page by clicking the share button and selecting the platform you’d like to post to. You can also click on the post title and grab the post page URL to link directly to a platform.
Adding teaser text to my posts
Teaser text offers non patrons and patrons who don't have access to a post a glimpse of what you're offering at that tier.
Your posts' teaser text defaults to the first 140 characters of the text body section of your post. You can customize teaser text while creating your post, or add it later when editing a post. When someone clicks on the social media post, they’ll be taken to a locked post page where they can become a patron.