You need a job offer and also an approved LMIA (this is something your employer has to obtain). You can't obtain a work permit based on the job offer alone. Typically, it's difficult to find employers willing to go through the LMIA process (they have to prove no Canadian could be found for the role) - however some people are certainly successful. As for the type of job, yes - it can be a job with a pizza place. However if the job you go for in Canada is too different from your past education / experience - CIC will sometimes refuse the work permit. For example, if have a number of years of work experience in banking and then suddenly want to apply for a Tim Hortons job in Canada, CIC may refuse you.
