You can set the time you need to schedule pickup for an order, ranging from 3 days to as long as 11 days. This feature on Elanic is called 'Days to process an order' and can be updated from Edit profile -> Store.
Suppose you are a reseller or importer who does not hold inventory, you would need more time to either procure the product or arrange for a pickup. Suppose you are a designer or someone who makes customized products, you need more time to customize the product. This is exactly why let you choose the time required to schedule a pickup.
This information will be shown to the buyer before placing the order. If you have chosen for 8 days, the buyer will see 'This product will be delivered in 12-15 business days'. The order will fail automatically if you do not schedule the pickup within the specified time.
Please note that the chosen time for pickup is applicable to all your orders, not just a selected few. You will not be able to have different pickup time for different posts.