The foremost thing to decide is whether you want to do content writing as a hobby or take up as a career.

Since you are asking this question, I believe you want to take it up as a career. If you are serious about content writing as a career, I would recommend to first brief yourself about the industry.

What are the latest trends in content writing? The different writing styles? What niche you wanna write in?

This article will help you kickstart on how to become a content writer and what training to receive: https://writerena.com/start-freelance-writing/

For any more questions, ask them in the comments below.