The Writers Marketplace is where employers can find your profile when they are looking for writers to handle their upcoming projects. If they like what they see in your profile, they can message you directly through Writers Work. You have to opt in to be featured in the Marketplace, and you can do that from your profile.
You can enroll in the Writers Marketplace once you complete your profile with a title and description as well as at least one item in your portfolio. As soon as you add these components, they will save automatically. Once you do that, just click the box at the top right corner, and your profile will become visible in the Marketplace. Here's a quick look at what to do: