In order to be able to build and submit your iOS app an invitation to your Apple Developer Account is required.Note that this will only work if you have an Organization Account.Below you can find more details on how to invite users to it.

1. Access the Apple Developer website clicking here. On the top right section, you can click on "Account" to be redirected to the login form.

1. You can then insert your login credentials to sign-in into your Apple Developer Account

1. Once logged in you will see your Apple Developer Account Dashboard. There you can click on "People" in the left sidebar.

1. You will then be requested to access your App Store Connect account to invite users, you can click the button that takes you there

1. Now on your App Store Connect dashboard, click the "+" icon to add users to your account:

1. Add the details for the user that you want to invite and click "Invite"

1. That's it! The user will receive an invitation his email, and he will need to accept it in order to become a member in your Apple Developer account