Because there are so many areas to explore as a Graphic Designer, there tends to be a requirement that you do three years of tertiary study. This allows you to be able to learn more about website visual design, studio art, computer design, motion graphics, print, typography, or any other styles and techniques you may use throughout your career. You would also will learn more about design theory and build your understanding of the design process.
For many of the graphic design courses, you may need to have created a portfolio first (for example, showing some of your illustrations, painting, photography, digital design, or video).
Graphic Designers often get their first jobs in advertising by developing a 'book'. This is a portfolio of designs you have created. These don't have to be real things that have appeared in the world. They are speculative - how you would create images which showcase products and brands that you've chosen. A 'book' allows a Creative Director or creative team to see how you think, get a sense of the quality of your creative thinking.