In case your publisher does not have an account to the Publisher Interface, you can create one from vene dash. Go to the publisher details in vene dash and click on the tab "Publisher Access"
Here you can see that the publisher has not created an account. By clicking on "Add user", entering the details and confirming by clicking on "Yes", you'll have created an account, which you can forward the credentials to your publisher. The publisher just needs to verify their email and is ready to go.