There are different categories of this which are

Family Class - the applicant is sponsored by family members,

Business Class - the applicant is self employed or an investor,

Skilled Worker Class  - the most common as it is for people with transferrable skills and education.

Provincial Nominee - Each province offers a Provincial Nominee Program (PNP) which is where you apply directly to that Province showing what skills you can provide and the commitment you have made to that Province. Once they approve your application, it is approximately 7 to 9 months to receiving permanent residency. In order to take this route, you must have a job lined up.  It is a three stage process: apply for work permit, apply directly to the Nova Scotia Nominee Program, apply to London for permanent residency. There is less information required and the applicant does not have to measure their skills, education etc as with other classes. 

In many posts and blogs, Permanent Residency is known as PR.