How do you become a referee for a math journal? I am in the early stages of my career (post PhD) and I would like to referee papers to (1) get the experience and (2) be exposed to unpublished writing to learn to improve upon my own writing.
How do you become a referee? Can you register?
Edit: I'm not asking about reviewing.
Generally, you would publish in Journals, and the Section Editors will descend on you like vampires in search of fresh blood asking you to do reviews.
If you have trouble breaking in, talk to a mentor, and ask them if they can recommend you to the section editors (in place of themselves) for any refereeing jobs that are really up your alley.