Select “Customs Forms” from the left side Menu and click on “Pick List” menu

On “Pick Lists” page, click on “+Add New Pick List” to create new List and click on the “List Name” to rename the List

You can add various fields associated with the products

Now, select “Customs Forms” from the left side Menu and click on the more icon on the list

Choose a customer field and click on the pencil icon  to edit it.

Then the “Customer fields” dialog box pops up as shown in the image below

When you click on the “Dropdown” field, you can see the names of pick list in “Drop Down” field

Chose a list from the dropdown option and click on "Save" button to save the changes

On the web catalog, users can see the drop-down option in the order cart