The deadline for delivering an order takes into account the "cost periods" defined for the five stages of the logistics route:
That is, for each of these steps you can define a cost time - and the delivery time that your customer will see at the checkout is the sum of these cost times.
The cost times for the stock and dock are defined in the setting screens of each of these steps, in the Inventory & Shipping module > Dashboard .
The cost time of the carrier is defined in the freight table, sent to VTEX through the carrier configuration screen, also in the Inventory & Shipping module.
Through freight simulation, you can check how the delivery time for a specific order has been calculated. Understand how in the article Checking how an order delivery deadline was calculated.