How to Convert uppercase to lowercase in excel?

Hi,
I have one excel document with all letters in capital. I want to convert it to lowercase. Can anyone help?

Thank you in advance.

Use the LOWER function to convert all uppercase letters in a text string to lowercase.
The LOWER function is in the Text category in the Insert Function dialog box.

Example:
Text in uppercase: GEORGE W. BUSH
The function: =LOWER(A1)
Result: george w. bush

Follow this Microsoft link: How to change the case of text in Excel

To convert the uppercase to lowercase select a range of cells, then invoke 'Selected Area=>Convert=>Text Case to=>There you can convert text cases to proper case, upper case, or lower case.
You can also select a single cell in a table's column, invoke 'Column->Convert->Text Case to->...', this will convert the entire column's text cases to proper case, upper case, or lower case, and the converted values will be placed in a newly inserted column next to the original column.