1. Role Definitions: ARIA roles define what an element is, such as a button or a banner. Screen readers can interpret these roles and convey the information to the user. 2. State and Property Definitions: ARIA allows you to define states and properties like `aria-expanded` or `aria-hidden`, which help users understand the current state of interactive elements. 3. Navigation Landmarks: ARIA can help define navigation landmarks, making it easier for screen reader users to navigate through the email content.