Not necessarily, although it does help strengthen your visa application.   If you meet a skills shortage and have at least a year of full-time experience in any one of 50+ high-demand professions, you can apply for a visa under the Federal Skilled Workers programme.   Should you wish to relocate to Canada and not have a profession within that skills shortage list or not have sufficient experience, you will need an offer of employment.   Employment and Social Development Canada (ESDC) must approve that offer as an ‘arranged employment’ scenario.