The main toolbar can be used to access parts of the program without having to use the menu bar. This feature works much like the Iconbar in earlier versions of Quicken.
From the menu bar, Click Edit, Click Options, Click Customize Toolbar to open the CUSTOMIZE TOOLBAR window.

OR
Clicking on the CUSTOM button on the main toolbar will also open the CUSTOMIZE TOOLBAR window. Using the CUSTOM button allows easy access to this window to make changes to the toolbar when desired.

Click on SHOW ICONS and SHOW TEXT at the bottom of the window if not already checked.
Within this window you can add items to the Chosen Buttons: list from the Available Buttons: list by highlighting the item you want to add and Click Add-> to insert the item into the Chosen Buttons: list. Likewise, to remove item(s) from the Chosen Buttons: list, highlight the item in the list of Chosen Buttons:, Click <-Remove and the item is removed from the list.
While items can be added or removed from the Chosen Buttons: list at any time, some of the Available Buttons: you might want to consider adding to the Chosen Buttons: are: Account List, Backup, Category & Transfer List, Class List, Exit, Memorized Transaction List, Print Checks and Write Checks. When finished making additions or deletions to the list of Chosen Buttons:, Click OK to close the CUSTOMIZE TOOLBAR window.