Slack Connector allows you to add, manage and configure notification streams on three different levels. You may set up notifications for a single issue (using Issue Tools), any issue in selected project (using project setup page) or for any issue in your JIRA (using global setup page).
You may additionally configure filters for each notification stream separately when you set up a notification stream or later on by reconfiguring an existing one. You can find more information on Filters and Events documentation page including information about the issue fields supported in notification filters as well as the full list of events that we distinguish in the process.