Gravity Forms can be used to collect submissions that can easily be made into Posts without requiring the authors to generate content with the WordPress dashboard.
First activate the Gravity Forms plugin in the Plugins section of the Dashboard for your site. This will add a Forms section to the Dashboard side menu. From there, you can create a new form with the New Form option.
The Post Fields question options allow you to customize what fields you would like to be submitted as part of a post submission. The fields use a drag-and-drop editor allowing you to populate the form with desired form fields in any given order. Clicking a given field will open up more options for that specific field as well as some settings that apply to the entire post submission.
Post submissions will appear in the Form – Entries section of the Dashboard but more importantly, in the library of Posts for the site. If the Post Status was set to Draft or Pending Review, the post will remain unpublished until an admin on the site reviews and publishes it. Setting the Post Status to Published bypasses this step and publishes the post upon form submission. When published, posts will feed into the category in which they were designated.