Mobile application for multiple organizations

Hello everyone, we have a mobile application being distributed through Google Store and have a list of users, organizations, and an M2M application with attached API.
We’re trying to figure out how to distribute the application so that user can login via username and password in native application flow, but so far no good because in every scenario we’ve seen it requires to have ClientID which we cannot embed into the mobile application.

Can anyone suggest a scenario for such flow so that ClientID is not embedded into mobile application?

Many thanks!