@hamasat, are you sure that you’ve read our documentation on publishing to the App Store? It describes much more than just authentication codes. Any suggestions that you can provide on how to improve that document would be greatly appreciated!
Just a heads-up that in order to use our process for publishing you will need to follow the procedure described in IMPORTANT: Two-Factor Authentication & Publishing to iOS App Store on Thunkable Cross Platform ✕ to turn off two-factor authentication for your apple account. We are working hard to change that requirement.
-Mark