How does a digital download reach the buyer?
Updated
The normal sequence
A digital download reaches the buyer automatically. The buyer pays, the payment processor confirms the sale to the store, and the store creates a private download link for that buyer. The link is emailed and usually shown on the confirmation page too. You send nothing by hand.
If you are attaching files to emails yourself, something is set up wrong.
Why links are personal
A good store gives each buyer their own link, often with an expiry and a download limit.
One leaked link then does not become a free copy for the whole internet, and you can see who downloaded what.
Where delivery goes wrong
The email lands in spam. The buyer typed their address wrong. Or the link expired before they opened it.
All three are common, and all three are the buyer’s experience of your product. Plan for them.
Set it up to survive that
Show the download on the confirmation page as well as in the email. Let buyers ask for the link again with their email address.
Be generous with expiry and download limits. Tight limits create more support work than piracy ever does.