I'm in a similar situation and would like to know the answer as well. How do we publish (and later patch) on clients developer accounts? Davidolesch - what do you exactly mean by "grant access to their account"? Login and password? Or would and invite to their team be sufficient? In that case what happens with provisioning profiles and certificates? I have published numerous apps under my own company's account, but I'm clueless on how to do that for someone else...

Sorry for the ***** but this is still the top listed result in Google. I'm failing to find any info on what is the most convenient way of publishing and app for a client. How did you manage Rigald? One way would be to upload the app to my account and the transfer the app to the clients account (there is a "Transfer app" option i AppStoreConnect). However I think this will create issues when the app will need to be patched. My clients have their own developer account, but they are clueless on the whole process and in general technology and asked us to do it for them. Another, and most obvious, option would be to get the login and password from our clients, but this sound sketchy and with Apples 2FA now everywhere this would also be very inconvenient. Can anyone who develops apps for clients pitch in?