Epics are a great way to organise your individual tasks into larger bodies of work. An epic is essentially a large task (or user story) that can be broken down into a number of smaller tasks or stories. Epics allow you to establish a hierarchy for your backlog so that you can start planning longer term outcomes.
From our blog: Gain birds-eye view across your boards with epics 🦅
From our blog: 4 ways to scale your Trello workflow to multiple boards