Coupon Discount Field

I need to give some client discount for the service booking that they make sense the Buy a workshop which then includes a online session once a week for 6 weeks, but they need to do the booking for the session through OSB. 

On testing, the Coupon field does not show in the registration form. How and where do I activate that?

Hi,
If a coupon is available, the Coupon input field will appear on the Checkout page.
Please make sure you have created and enabled the coupon. If you still don’t see the field, let me know and I’ll help you check further.
Best regards,
Dam

Will it only display when there is an active coupon created?

They are normally link to an individual, or a group, with a maximum number of times.

So, it is not a standard field that will always display?