There are three formulas which you can use for this purpose:
1. =UPPER()
Changes the whole text to upper case.
2. =LOWER()
Changes the whole text to lowencase.
3. =PROPER()
Changes the first letter of all the words to upper case and the rest to lower case.
The syntax of all the three formula is simple: Enter the cell containing the text that you want to change in the brackets.
The screen shot below shows the use of the three formulas: