Tasks are starting points of any custom integrations.
Each task is built using Liquid code. This is the same Liquid syntax that you know from Shopify, however it has few extensions. All available extensions are detailed in this documentation under Liquid section.
There are four different types of tasks:
Input - this task accepts a file uploaded by user as an input. File is uploaded through user facing dashboard. Useful when you need to import data in bulk or modify Shopify object based on source file.
HTTP - this task will be triggered anytime autogenerated endpoint is called.
Scheduled - runs on a schedule. It can also be trigger anytime manually by the user.
Event- triggers anytime one of the Shopify events is detected, like new order, updated customer etc.