This feature is only available for external products.
To do this:
- Edit the Order page and go to Payment Settings on the left side bar menu.
- Select External Product on Give Access To.
- Next is choose the product on Select External Product.
- At the bottom of the settings, click the More Options. Switch ON the Enable Quantity select option.
That’s it, just click SAVE.
The quantity option will now appear on the Order page and the total changes based on what they have selected.