An important part of keyboard accessibility, tab order describes the order in which elements come into focus when navigating using the tab key.
The tab order defines the order in which elements will receive focus when the user navigates via the keyboard. The tabbing order may include elements nested within other elements.
The tab order should follow the visual flow of the page: left to right, top to bottom – header first, then main navigation, then page navigation (if present), and finally the footer.