You can display an RSS icon that users can click to subscribe to new Posts that are displayed on an element on a site page. This process is the same to turn on the Subscription "bell" icon.
These RSS feeds will also allow you to use third-party services, such as dlvr.it, in order to post items on social media.
To display an RSS icon or the Subscription option for a Posts element, you must first set a default board post page for the Board the element is set to display. If you do not already have a default landing page for the Board, create one before adjusting the RSS settings (you can always set the page to be hidden from site navigation if you don't want it to appear as a clickable link.)
To display RSS feed links on Posts elements:
Go to Posts in Composer.
Open up the folder that contains the Board, hover over the action menu, and click "Settings" to open up the Board settings.
Make sure the "Enable RSS" checkbox in the "Default Board Post Page" section is selected. There is also a checkbox for "Enable Subscriptions" if you would like to select that option.
In Composer > Pages, go to an element that displays posts from this Board. Open the Element Settings, and in the "Controls" section, select the "Display alert icons" checkbox.
The RSS icon will appear on the page, above the Posts element.