fixed date in numbers template Is it possible to use the =today() function (or something else) to insert the current date but then not update each time the file is opened?

I want to create a numbers template for my invoices. I'd like it to auto fill invoice date and date due then, when I save the document, store the values, not the function.

I am creating templates on my mac then using the inumbers app on my iPad.
i'm guessing this is what you are looking for  =NOW()