If you want to change a large block of text from lower case to upper case, your best bet is to use a hotkey combination that will make the change automatically. Hotkeys, also called keyboard shortcuts, are combinations of keys that execute specific commands when pressed together in a certain order. Some hotkeys, such as "CTRL-C" to copy selected text, are universal among all programs. The hotkey for changing lower case text to upper case text in Microsoft Office applications is "Shift-F3," but other programs may use a different hotkey.
Highlight the text you wish to convert from lower case to upper case.
Hold down the "Shift" key, then press the "F3" key if you are using a Microsoft Office program such as Word, Excel, PowerPoint or Outlook. The text will change to all upper case.
Consult the manual or Help menu of other programs to find the hotkeys if Shift-F3 does not work. Some programs allow you to create you own hotkeys. The open source program, OpenOffice, for example, allows you to create custom hotkeys. Select "Tools," "Customize," then "Keyboard" and you can choose your own hotkey for converting text to upper case.