Teamwork makes the dreamwork! We're glad you have more people joining your PRX Publish adventure. To be add staff members to your Publish account you will need to be an admin of your account. If you are, then please ask your coworker to create an account with PRX at exchange.prx.org. Once they have a username you can log in to your own account at exchange.prx.org and go to My PRX> Manage members and add by username.
We ask team members to have individual accounts rather than one general account for security and flexibility. Having your own account allows you to work with multiple teams without juggling different login credentials, and you can add or remove people while your team changes without altering account credentials. And on the whole, it is just better security.