Working Holiday is for people who do not yet have a job offer from a Canadian employer, or for people who would like to work in more than one location or for more than one employer in Canada.
Under this category, you would get an open work permit that allows you to work in most Canadian jobs. There are some jobs you could not do, however, or jobs where you would need to undertake a medical examination first, before doing the work.
With Working Holiday, you could earn money with temporary work to fund your vacation and travel in Canada. You would also be able to gain work experience, either in one job or in multiple jobs with two or more employers.