Enabling Shipped Post Purchase upsell gives your customers another opportunity to add Shipped Shield/Green to their order. It will be offered as an add-on after the customer has checked out.
If enabled, any Shipped add-on will be treated as another payment transaction.
To enable Post Purchase Upsell:
Go to Settings and click into “Checkout”.
Located “Post-purchase page” section
Select "Shipped Suite".
Click “Save"