It's important to establish buyer personas for your business to help segment your audience and create stronger marketing campaigns. Buyer personas are fictional, generalized representations of your ideal customers. They help you understand your customers (and prospective customers) better, and make it easier for you to tailor content to the specific needs, behaviors, and concerns of different groups.
The strongest buyer personas are based on market research as well as on insights you gather from your actual customer base (through surveys, interviews, etc.). Depending on your business, you could have as few as one or two personas, or as many as 10 or 20.