If you want to visit only, then you'll need to apply for a visit visa. Note that it is illegal to work while on a visit visa:
http://www.cic.gc.ca/english/visit/apply-how.asp
If you wish to come to Canada to work, then you will first need to find an employer who is willing to hire you. That employer will then need to obtain an approved LMO (labour market opinion). If the LMO is approved, you can then apply for a work permit:
http://www.cic.gc.ca/english/work/apply-how.asp