Checkbox for option to autofill Shipping address the same as billing address

I have searched and searched on the internet for a solution to this but still I have not found a solution. Please help!
How do I insert and edit the cshtml for a Checkbox for option to autofill Shipping address the same as billing address?
We are using Nop 3.60 and have 1 page checkout plugin. When the customer checks out they have to manually fill in Billing and Shipping address. I want to insert a button that allows them to check it so it autofills the shipping address to be the same as the Billing address for easier checkout.

Hi, 

If you are using our One Page Checkout plugin, it has a setting in its administration, called "Enable Ship To Same Address by default". Just enable it and the shipping address will be the same as the billing address.

I hope this helped !