When creating a new project or new submission, you can add your co-writer(s) by selecting Add Another Writer after entering your information.
If you would like to add a co-writer to an existing project, you can update it on the project page by selecting Update Project and clicking Edit Writers.
If your co-writer has a Coverfly profile, adding their email address will allow the project to appear on their public profile, if the project is Discoverable. However, only you will have the project on your personal writer dashboard and you will need to manage all submissions. Project management cannot be shared across writers.