how can I make a professional website and sell it on Upword or Peopleperhour and how can I make the site able to add any post or reporter
This question lacks descriptive terms of what you’re actually trying to accomplish.
If you have the skills the work will come.
What do you mean by how do you make a site? If you mean you don’t know how to code than take FCC courses.
If you mean how do you market/sell it, then again you should be reaching out to potential clients daily.