Facebook will not allow developers pre-fill messages. Developers may customize the story by providing OG meta tags, but it's up to the user to fill the message. This is only possible if you are posting on the user's behalf, which requires the user authorizing your application with the publish_actions permission. AND even then:
Learn how to create a Facebook share link without using JavaScript, including tips and solutions for effective sharing.
In the facebook developers console for your app, go to App Review-> Permissions and Features. Set the public_profile and email to have advanced access. This will allow all facebook users to have access and these two settings are auto granted. Ensure the Access Level indicates Advanced Access
How to resolve Facebook Login is currently unavailable for this app ...
Notice that you can play around with the fields you're querying for, the username and the objects you're requesting (in this case, videos). However, also notice that you must create your own access tokens and that queries you make will have your name on them, (so don't abuse this). You can play around (and create your own access token) with Facebook's API in their Graph Explorer Tool: https ...
The Facebook SDK for Unity gets the wrong key hash. It gets the key from "C:\Users"your user".android\debug.keystore" and, in a perfect world, it should get it from the keystore you created in your project.
I want to add facebook share button on my website, that should just post my website's content on the wall. Can anyone help me?
How to add facebook share button on my website? - Stack Overflow