Some projects contain information employers might not wish to circulate freely. To regulate such information and keep it within Freelancer.com, there is the Private project upgrade. With this upgrade, your project’s details will not be accessible to any search engine. It provides a measure of protection because only users who are logged in will be able to see the project’s details.
You can upgrade projects while they’re being posted. On the Start a Project page, just tick the box next to the Private option and click Post Project Now. The Private upgrade is only $19 USD.
The Private tag will not appear when the project is listed on project search results from Browse Projects. The tag will only be shown on the project's page itself. Freelancers will then be made aware of its nature and asked to keep its details off the record.
To know the difference between the Private upgrade and deleting your project, please read this article.