The Order Details form is a form that sales reps and B2B Storefront customers can access from the Cart view of their order. This form contains fields  with additional information about the order. This information is saved along with the order and can be printed on the Order PDF that is emailed, and integrated to the ERP.

If you mark a field Mandatory on the Order Details Form this means the order will not be able to be submitted until the user opens the form and fills in this field.

Mandatory fields are marked with a red star on the form and users will receive a warning message listing the required fields if they try to submit an order without filling in this field, the form will automatically open and once they enter a value in the field and save the order will be submitted.

Edit the Transaction Type and in  Views and Forms -> Transaction Details -> Details Form, edit the configuration.

Click on the edit (pencil) icon next to the field heading and select the check box for "Mandatory".

(Selecting "Read only" will make the field non-editable.)

 Here is what it will look like on the form :

To force the Details Form to pop up at any point in the Order workflow use the Open Form action:

This action opens the Details form. If the form does not contain fields marked as mandatory it will not be opened. Selecting "Always open form (even if no mandatory fields)" will open the form even if does not contain mandatory fields.