If you want people to share something you publish on your Facebook wall, you must first make sure the post itself is shareable. You must publish your post so that your friends to share it. The steps for
how to make a post shareable on facebook:
Choose the "What's on your mind?" section on your Facebook home page.
Under your Facebook profile name, select "privacy dropdown menu".
Select "Public" to allow anybody, both on and off the Facebook website, to share the post.
When finished, click "Post" to display the message on your wall.