Usage of lightning:tab

A lightning:tabset displays a tabbed container with multiple content areas, only one of which is visible at a time. Tabs are displayed horizontally inline with content shown below it. A tabset can hold multiple lightning:tab components as part of its body. The first tab is activated by default, but you can change the default tab by setting the selectedTabId attribute on the target tab.

Use the variant attribute to change the appearance of a tabset. The variant attribute can be set to default, scoped, or vertical. The default variant underlines the active tab. The scoped tabset styling displays a closed container with a defined border around the active tab. The vertical tabset displays a scoped tabset with the tabs displayed vertically instead of horizontally.