Process settings are found in upper right corner of the modeler and on the process page by clicking on the cog wheel.
There are three areas for editing model and application settings:
General - select whether the process should be available as a Call Activity or not, read more in the article Reusable process.
Permissions - edit the user and group permissions to the model and the application, read more in the article Process permissions.
Sharing - enable/disable whether the process should be available to share to anyone, read more in the article External weblink for process model.