In Express Entry, applicants are ranked based on the information they provide (i.e. Age, Education (as per Canadian Standards), Language Exam Score (IELTS/ CELPIP/ TEF/ TCF), Experience, Job Offer within Canada, and Adaptability) and then selected for immigration through regular Express Entry Draws to apply for Canadian Permanent Residence.
The main difference between these two immigration programs (Express Entry and Provincial Nominee Program (PNP)) is that if applicants obtain permanent residence through the Express Entry Program, they can move anywhere in Canada (except for their first landing in Quebec, because Quebec manages its immigration program, namely the Quebec Selected Skilled Worker Program (QSSW)), whereas if permanent residence is obtained through the Provincial Nominee Program (PNP), they’re unable to relocate.