Personas are visual stories that describe actual customers. Personas draw a detailed picture of the user, what they want to accomplish, what knowledge or skills they may or may not have, and why certain things may be more important to them. The products or services you design try to solve these customer problems. Personas help the team focus on user-centered design.
When creating personas, consider pulling from lots of different categories. I've used Porter's Five Forces to create these categories. You should consider anyone in your supply chain or anyone who influences your bottom line.
People who will buy or use your product or service.
People who will sell your product or service for you.
Policy Influencers or Regulators
People who recommend your product or service to potential customers.
People who sell their own product or service to a similar demographic as yours.
People who influence the rules about selling your product or service.
People who may manage or administrate your product or service, but are not customers.