correct, it IS available on most types of shipments. Cost is 13 cents for electronic shipments, and 45 or 55 cents on all others
You can use Delivery Confirmation with:
First-Class Mail® Parcels - Envelopes and small packages weighing 13 ounces or less. Applies only to boxes or envelopes measuring at least 3/4” at thickest point.
Priority Mail® - Cost effective delivery in an average of 2-3 days.
Package Services Parcels - Send small and large packages, envelopes, and tubes. Includes Parcel Post®, Media Mail®, Bound Printed Matter, and Library Mail.
Standard Mail Parcels - Items weighing less than 16 ounces can be sent at discounted presorted and automation rates. Available only for pieces subject to the residual shape surcharge and mailed at the Electronic rate.
Parcel Select® - Send large volumes of packages at a discount.