By default, all products use the Global Lead Time set in settings page. You can adjust this per product basis by following these steps:
Open Order product view
Enter your adjusted lead time
Click Save
Once a product has a customised lead time it is saved, and indicated by the delivery truck icon:
If you ever want to revert to using global lead time for any product, just clear the field and click save. You can be sure if the product is using global lead time by the globe icon in the field:
