Cannot create sub-task on Jira cloud mac os APP.

[Norman Zuo]

The step is here:

However, there doesn't have a chance for me to select Development Team when creating a sub-task.

[Nic Brough -Adaptavist-]

Yes, the app is not showing you a field that you have set required, so you can't create the issue.

You'll either need to make the field optional, or configure the app to show you the custom fields (I'm not familiar with it, I don't know if that is a code change that the authors would have to do)