I provide software automation services as a product on my store.
Usually, I agree with each customer to make a program for him. After I finish the work I would create for him a draft order so he can pay the agreed fees.
I want to let the client download the file after he pays the draft order. Same as the Digital Downloads app but different downloadable files for different draft orders checkouts.
Or at least I can upload the file to my one drive and show the customer a download link after he pays.