To apply the same general modifier to several already selected dishes, use the Group applying of common modifiers operation.
To do this, mark the required dishes in the order and select the Common modifiers operation.
Then select the desired modifiers (you can select several) from the list and click Done.
Modifiers will be added to each marked dish.
The operation is available only for unsent dishes. If both unsent and sent are marked, the operation will not be displayed in the list.