Custom events can be sent to Liveform when a user performs a specific action on your website. For example you can send an event to indicate that the user has interacted with a particular feature on your website.
This custom event can then be used to create an audience within Liveform. Now you have the ability to target surveys at users who've interacted with that feature. This is useful if you want to survey those users, and ask them questions relating to that feature.
The following snippet can be used to send a custom event to Liveform