Hello everyone in this video tutorial I have explained how to create a DMG container folder in a very easy way using macOS native applications without using any third-party applications.
you can easily follow the described steps and at the end of this tutorial you will be able to: -
- Create a dmg container file. 
- Make it "read only" to prevent anyone from modifying it.
- Create a new simple application. (these are the complete steps)
- Add your application inside the DMG container.
- Customize the container folder background.