Not yet for shipping. The Stackably online store does not currently offer shipping rates at checkout or carrier shipping labels. Online orders are fulfilled locally: customers collect them in store, or you can offer local delivery through Uber Direct's driver network. Both of those are included and are covered in Does Stackably offer in-store pickup and local delivery for retail orders?
What that means
Customers cannot choose a carrier shipping method or pay a shipping charge on the online store.
Merchants cannot print a carrier label from an order.
Customers can order online for in-store pickup, with an optional pickup time chosen at checkout, and can choose local delivery where Uber Direct is turned on for your location.
What to use instead
In-store pickup. Every online store takes pickup orders; the order lands in your POS and the customer collects it at the counter.
Local delivery with Uber Direct. A flat per-delivery fee (typically $4.00 to $5.95, paid by the customer at checkout) and a driver from Uber's network, for customers within about 10 miles. See Delivery for your own online orders with Uber Direct.
Mailing an item. For a customer who needs an item sent further afield, create an invoice from Finance with a shipping line added as a one-off item, let them pay it online, and ship it yourself.
If carrier shipping is essential to your business, tell your Stackably representative so it is counted when the feature is prioritised.