This task is triggered anytime an event in Shopify happens. When task is created, Shopify webhook is created as well. The payload of the webhook will be available for your use inside task's code.
Here is an example of how you can add a tag to order anytime new order is created.
Object payload is preloaded anytime task is triggered that is why it is available for us at very first line of the code. For readability we assign payload to order variable.
If you are not sure what is inside webhook payload you can reference this site provided by Shopify: