Use the software only for sale download

Not quite sure what you are asking. Could you provide further details?

That it will be preset as a downloadable product

You can set up your products so that they can be downloaded. Here’s how to set that up: https://docs.woocommerce.com/document/digital-downloadable-product-handling/

I know it
I run a multi-vendor store so I have to set everyone up in advance so it will be locked on this option