Thank you very much for your answer. Does the fact that I switched my career totally in Canada matter? For example from marketing in my home country to health field in Canada. If I apply under FSW I will have to show my marketing experience, but I won't continue this career in Canada, since I have already finished college here and am working in different field. Does this matter at all? Because I thought they give you PR under FSW program if you continue working in same field here in Canada.
You're free to pursue any career you want once you get permanent residency, whether that's a past career, your current career, or a completely new, unrelated career.
Generally, most applicants simply claim their 'primary' career as the career in which they have the most years of experience, for ease of application, and to maximize the points they can get for eligibility or CRS points when they are pursuing Express Entry (even though, really, you only need to have 1-year of continuous full-time experience in your primary NOC to satisfy eligibility, and then all of your other relevant experience is subsequently added together for points purposes), but it doesn't actually have any bearing on what career they will have to choose once they become a PR.
From a logical perspective, if IRCC cared whether you were going to work in a specific career when you received PR, the programme would probably provide preference to certain careers for which demand is greater, but this is not the case; the Express Entry programme really appears to be geared toward bringing in 'skilled' persons in general, regardless of what those skills are and whether they plan to use those skills in specific fields.