You have created an individual Apple Developer Account (sole proprietor of your business)?
Then we need the "app-specific password" from you, to successfully submit your app to the Apple App Store.
It's quite an easy process to create this.
Log in on this page: Your Apple-ID-Account
Within the menu "Safety", click "create password" under "app-specific passwords".
As a name you can put in "My app".
Now the app-specific password will be displayed. Copy the password and send it via mail to [email protected].