Examples
A company which provides courses to train people to be plumbers refuses to enrol women because its directors assume that very few people want to employ female plumbers. This would be direct discrimination.
An agency which finds employment opportunities for teachers in schools offers placements only to white teachers based on the assumption that this is what parents in a particular area would prefer. This would be direct discrimination.
An agency advertises job vacancies on its website. It will need to have the website checked for accessibility and make reasonable changes to enable disabled people using a variety of access software to use it.