User settings
Select the event and the role that you will have when you want to get notified.
Events are triggered in JIRA when changes are made, such as updating an issue or commenting an issue.
Transitions in JIRA is by default triggering a Generic event. This can be changed in your workflow by editing the post-functions. For instance you might want to change the last transition in your workflow to trigger a Issue Resolved or Issue Closed event.
There is a option to limit the notifications to only a list of Projects or to a custom JQL Filter. Filter can be any custom JQL filter.
Global settings
The global settings can be reached by going to System > Add-ons and goinr to the section Inbox for JIRA.
This page control the default user settings for your organisation. Changing these settings will reflect on each user that has not yet changed their own settings.
Users that changed their own settings are overriding the global settings.