Function to automatically replace/rename specific text

Function to automatically replace/rename specific text

Hi, new to Zoho CRM, and hoping the great community can offer some expertise!

I am wanting to build a function whereby I can identify specific text strings and automatically replace them with an alternative.

e.g. "Mailing Country" field on a Contact.
If the field contains "US", "USA" "U.S.A" I would like it to change to "United States"

Any advice on where to start appreciated.