A dialog box in Excel is a form that allows users to input information and make choices about different aspects of a spreadsheet.
It is not always necessary to access features and options in Excel through a dialog box. Many of the formatting features found on the Home tab of the ribbon in Excel 2007 and 2010, such as the bold feature, can be found on single choice icons that a user clicks on once to activate a feature and clicks on it a second time to turn it off.
All functions, found on the Formulas tab make use of dialog boxes. The dialog box allows the user to set the location of data and to input other options to be used as arguments for the function.