A very common example of bulk actions is sending an email to a selection of clients in one action rather than going in and emailing each client individually.
To do this, just select one or more rows in your Insight grid. That will show you the bulk action icons.
Any bulk actions will appear after the edit icon.
Additional bulk actions can be found by clicking on the ellipsis button.
All you need to do now is click on the email action and off you go!