Problem: I have a list of "products" from my customer with various text/images. On a webpage. I would like to be able to make a function for them to MANUALLY push a button and have a facebook post CREATED for them, but NOT send automatically.
Reason: They want to control and edit it before posting, but save time in creating and getting the facts automatically inserted. They will just post as the currently logged in user.
I have attached an example screenshot of what I would like my customer to see after pressing a button.
I have tried: All kinds of things with a sharebutton. Alas, theres no page to share....and limited things to do with content.. I am unsure if I need to create an app, or if it can be solved by posting the info somewhere
What to do?

This can be done through in Facebook Page Composer via an unpublished Page post that isn't immediately published on your Page or in your News Feed.
Unpublished Page posts allow Page admins to manage the delivery of advertising content using audience filters. These scheduled or draft posts are delivered on future publication date or through promotion within an ad set.
Once your customer is happy with it, he/she can publish or schedule it.
See more details on this link: https://www.facebook.com/business/help/357923380922077?helpref=faq_content