Edit the file in Admin → Downloads and give it a price. You will need your PayPal credentials in the payment settings first.
Access is granted when the payment settles, not when the buyer returns to the site. Those are different moments and only the first is proof of anything.
A file can also renew — a price and a period — and a renewal extends the existing access rather than replacing it.
🚨 php tools/convoro purchases:sweep reports sales that got stuck and access that has lapsed. It deliberately never decides: a payment that went through while its notification did not looks exactly like somebody closing the payment window, and only your provider's dashboard can tell those apart.