Hi,
I have card on file. Now i want to update/edit billing details of the card through apis. How can i do that? When i refer doc, I can see only list,create,retrieve and disable apis.
You’ll need to create a new card if the information for the existing card has changed. Please note that Square does update card expiration date and CCV when the information is provided from the card networks when they update the cards. 
please share the c# code to update card cvv or expiration date.
We currently don’t have an UpdateCard endpoint. If you need to update information on the card you’ll need to call CreateCard and create a new card on file for the customer.