Login to your Apple developer account at https://developer.apple.com/account/
Go to https://appstoreconnect.apple.com/access/users once you are logged in.
Click the small blue ADD (plus sign) icon, towards top of page, to add a new admin.
Create a new user by checking the ADMIN box and APP MANAGER box, as seen below.
Use exact info as seen below:
This will send us an invite and allow us to send the app through your apple account.