What should a service always deliver to customers?

Applications are a type of resource and a technical mechanism used to deliver a service; they are tools that may help create value but are not what a service is defined as always delivering.

Infrastructure is an underlying resource that supports service delivery but is an input or enabler, not the outcome that customers receive or the reason they engage with a service.

ITIL defines a service as a means of delivering value to customers by facilitating outcomes they want to achieve without ownership of specific costs and risks. Value is the central and defining purpose of every service - it is what justifies the existence of a service and is composed of two core components: utility (fitness for purpose) and warranty (fitness for use).

Resources are internal service assets used in producing and delivering a service; customers consume the value created by those resources, not the resources themselves.