It can be anything from online to offline, depends on ease of recruiter, but a resume analytic solution such as resume parsing software can help you to extract data from resumes and segregate into appropriate fields. It helps to reduce manual work and automates your hiring process.
As I can see the methods which you have listed, all of these methods do work for the recruitment but amongst them which one is the most effective, this answer will throw some light on the method.
Recruitment agencies are the most effective method for the hiring process. And you might be thinking why? I will give you 4 reasons why recruitment agencies work: