When you create a Transaction in Essentials through either a Procedure or adding it in manually, it is tied to a service in the background

To learn more about a service please follow the link below

To set up what can be discounted:

On this screen you will see a list of all of your services.
There is a column called Discount Applies which will let you know if a discount can be applied to that service from a glance.

If the particular service is eligible for discounts or if you wish to modify an already discounted service, click on the cogwheel next to the service and then click update

You can now tick or untick Discount applies and then update the service.

Please note, that the discount rate for the particular owner will still need to be set against the ownership in the horse record