Adding Custom Zoho App to an Existing Form in Zoho CRM

Adding Custom Zoho App to an Existing Form in Zoho CRM

Hi there, 

First off, I'm really impressed by these forums and the quality of the support from Zoho. Thanks so much in advance!

My question: Is there a way that I can add the code of a custom Zoho app to an already existing form within our Zoho CRM?

Background explanation: I found this great code snippet on the Zoho Creator Forums:  https://creator.zoho.com/sampleapps/format-phone/#Form:Format_Phone

I would like to add this code to the existing Phone Number fields in our CRM so that all future phone numbers are cleanly formatted.

Any assistance on how I can go about this would be greatly appreciated. 

Thanks again in advance!
Bill