a CTA (call-to-action) is a user interface element, typically a button, that invites the user to take a specific action as indicated by the label of the call-to-action element.

a CTA (call-to-action) is any type of user interface element used to actively prompt the user to take a specific action by drawing attention to the user. Typically implemented as a button that is visually designed and spatially positioned to create focus as well as invite an action from the user, a call-to-action is also generally related to a specific goal or task that the designer wants the user to complete.