There are a number of ways to find a freelance graphic designer. One of the easiest is to do a quick Google search. This will give you a list of designers in your area (if you're looking for someone local) or designers who work remotely.
Another option is to use a freelancer marketplace like Upwork, 99designs, or Fiverr. These platforms allow you to post your project and receive proposals from interested designers. Once you've selected a designer, you can then work with them directly through the platform, which makes payments and communication easy.