The category of skilled worker and professional involves those people who already have their university degree and experience in their profession within their own country like engineer, doctor or lawyer. Those who apply in this category must be good in at least French or English language (or both), which are the official languages of Canada.
As per CIC (Citizenship and Immigration Canada), people who immigrate under the category of skilled worker will be eligible providing that they had lived in Canada legally for 1 year as international student or temporary worker, they were already offered an employment in Canada, or they have 1 one year of least experience in any one of the occupations listed by CIC. There are many occupation listed by the CIC for those who wants to immigrate to Canada.