When placing an order through Optiply, we will pre-fill this date for you based on the supplier's lead time. You can update this date through Optiply or the API when it changes.
​
In Optiply go to the Deliveries page and change the date of the order by clicking on the small calendar next to the existing delivery date.

Change the date and click 'Apply' in the end

You can do the same for each individual product if you go inside the order and select the small calendar next to the delivery date of each product
​
​