Using client's apple developer account

Hello, my client invited me to his account as an admin. But his account is not an Organization one, it Individual. My Apple ID already has a paid apple developer account and I'd like to create a new app for his account (since he invited me as an admin). It shows his name under my name when I'm on the Add Apps page, but when I choose to Register a new bundle ID in Certificates, Identifiers & Profiles, it chooses my account not his. How can I create an app for him? Maybe he needs to change his account to Organization?

Using client's apple developer account
 
 
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