In the case of Onro, you should apply for enrolling in the Apple Developer program as an organization.
How to invite a new user to your Apple Developer account:
Log in to App Store Connect using this link: https://appstoreconnect.apple.com
Open the Users and Access section.
Click the '+' button in the top-left corner of the page.
Enter the new user's details. Add [[email protected]] as the new user.
Grant the user the Admin role.
Click Invite to send an invitation to the new user's email address.
Have the new user accept the invite in their mailbox to finish the process.
Once the new user accepts the invitation, you will be able to log in to the Apple Developer Portal using the newly invited user account.