The toolbar in any application can be a huge time saver. They come preloaded with buttons that do the most common tasks in the application, like save documents, reply to emails, etc. However, many apps have toolbars that can be customized by adding buttons, removing ones you don’t use often, or rearranging their position in the toolbar. These buttons can be done in Mail, Safari, and most other apps that use the standard OS X toolbar.
To get started, either choose VIEW, CUSTOMIZE TOOLBAR, or right click the toolbar in an area with no buttons and choose CUSTOMIZE TOOLBAR.
This will bring down a panel of buttons and options below the toolbar.
While this panel is showing, the toolbar is editable. Simply drag buttons you want added from the panel to the location on the toolbar where you wish it to stay. To remove buttons currently in the toolbar, just drag them off the toolbar and release. To rearrange the buttons in the toolbar, drag them to the position of your choice, then release.
In mail and some other applications, you can also choose whether you would like the buttons to be represented by icons (the default), text, or icons with text.
Customizing the toolbar can not only save time, but is a great way to discover features of the app that you may not have been aware of. For example, there is a REDIRECT button in Mail that will allow you to send a received email to a new recipient without adding the quote levels and other characteristics of a forwarded email.
Jason Merrill, Mac & iOS Consultant