Under the shipping methods: the days on offer (lead days, a cut-off hour, excluded weekdays and holidays, time windows) as plain selects, checked again when the order is placed. The date goes on the order and shows in My Orders, in the order e-mail, on the admin order page and as an orders grid column.
The delivery date under the shipping methods in checkout.
What it does
Lead days, cut-off hour, days offered, excluded weekdays and dates, time windows
Checked on the server when the order is placed
On the order everywhere: customer, e-mail, admin page, grid column
