Press Alt+F11 to go to the VBA editor, click Insert/Module from its menu bar
and then copy/paste this macro into the code window that appeared...
Sub UpperCaseText()
With ActiveSheet.UsedRange.SpecialCells(xlCellTypeConstants)
.Formula = UCase(.Formula)
End With
End Sub
Now, go to the worksheet you want to capitalize the text on, press Alt+F8 to
bring up the macro dialog box, select UpperCaseText from the list and then
click the Run button. If there are other worksheets you want to do this on,
activate the worksheet and then repeat the instructions from previous
sentence.