Use Toolbar + Menu Button command pattern when the number of frequently used commands are about 8 or less, and the remaining commands are not essential to performing the primary task of the application. The toolbar pattern exposes the frequently used commands. The menu button pattern exposes more of the command structure.
Commands are also exposed using context menus, a context panel or by the direct manipulation of content.
See toolbar for more details.
Web browser, File manager, Text editor, Email, Calendar, Image editor, Music player, Archiver
On mobile, a toolbar is diplayed as a group of primary action buttons.
If there are controls that need to be accessed often within the application’s primary tasks but the content needs as much space to be available as possible, you can add up to three primary action buttons.
The primary action buttons are at the bottom of the user interface and there cannot be more then three buttons.