Basically, in general terms, the provinces' nomination authorities are a substitute for the selection processes that the immigration act and regulations lay out in categories like skilled workers, or the Canadian experience class, or our business programs. They are an alternative economic program. They nominate a candidate and effectively move them into the final selection process.
As the 97% approval rate demonstrates, the federal official will normally simply be accepting the applicant as having met the selection criteria as long as they are assured that the applicant intends to reside in the province of destination and that they are capable of economically establishing. That is normally presumed from a provincial nominee certificate, and it's only in fairly exceptional cases that this would be looked at. They have to be sure in the case of business programs that it's not a passive investment. According to regulation, the provincial nominee business person must intend to be actively engaged in the functioning of the business.
At that point, the applicant has now been selected and they move to the final stages of process, which is a federal role to ensure that the individual is not inadmissible to Canada for health, safety, security, or criminality issues. Then the federal government issues the immigration visa and they are landed at port of entry in the normal way by our colleagues at CBSA.