Wordpress Module For Freelance Writers

I am interested in implementing the following module to receive specific texts from writers, preferably to my website.

I want to be able to customize the requirements, which would be:
Titles and subtitles - characters per title
Paragraphs - Words per paragraph
Keyword: Minimum amount of keyword in paragraph/title

Here is an example of another site implementing this model: http://prntscr.com/mpd5o0

Do you guys know how to implement this? Are there any Wordpress plugins available, or would I have to hire a freelancer for this? If so, approximately how much would it cost?

Hi, I could you please redirect me to that plugin please.