A definition of done is a shared checklist of the valuable activities required to produce software at different phases. An explicit and concrete definition of done may not seem too important on the surface. With experience, agile practitioners learn that the definition of done is critical to success. Without a consistent understanding of done, velocity cannot be estimated, but with consistency, a better quality and predictability can be achieved. The definition of done is the glue for a solid process.
To get here, go to Transform > Definition of Done from any level of the navigation menu. Here, from the Work Item menu on the toolbar, you can navigate between definitions of done for different items, such as story, feature, epic, psi, program increment, and post release. Clicking any of those items takes you to the page where you can set your own definition of done. You can edit any of them by clicking the Edit Done button on the toolbar.