Living in Canada won't qualify you for permanent residency. If you want to become a PR, you will have to apply or be sponsored under one of the following programs:
If i went to Canada and stayed with my friend on a holiday basis, but then found offers of full-time employment while i was living there. What would my options be for staying and working and living legally ? once im already in Canada.
The working holiday visa will allow you to come to Canada to live and work for a year.
Once that year is over, hopefully you will have found an employer who is willing to continue to employ you. If so, that employer will have to apply for something called a Labour Market Opinion to obtain approval to hire you. If the LMO is approved, you can then apply for a work permit that will allow you to stay and work. More information about the LMO and work permit processes are here:
Once you have worked for two years in Canada in a skilled occupation full time you can qualify to apply for PR through the CEC program. More info here:
You may qualify to apply for PR under some of the other categories. So it's important that you spend time going through options on the link I provided earlier to see what you might qualify for.