Associate at PwC Canada
I can only speak for those in Canada, so I'm not sure how much this will help but here's how it worked for me (and how it still works today):
1) Obtain a university degree from an accredited university
2) If your degree is business related, you'll want to select the accounting specialization (or "major")
3) If your degree is not business related, that's okay! After you graduate, regardless of your degree, you'll need to enroll in a post graduate program that offers the CPA "prerequisite" courses. A school that I know offers this is the University of British Columbia (you can google the UBC DAP program). DAP stands for "Diploma in Accounting."
4) Once you start step 2 or 3 above you'll want to begin networking with the Accounting/Auditing firms in your region. The best way to get a start is by getting in touch with your faculty and they will point you in the right direction. Most university's have "clubs" or "groups" specifically designed for this purpose. Ensure you network with a firm that has audit roles (that won't be difficult as all the firms have auditor positions).
5) The firms you begin to make contact with will communicate to you when application deadlines are and what positions they have open. They will also inform you on the specific application process for their firm.
Hope this helps!
Whilst in the process of step 2 or 3 (depending