Write a letter to a customer, client, or friend. You can create a letter for a specific individual, or create a form letter ...

Write a letter to a customer, client, or friend. You can create a letter for a specific individual, or create a form letter that you then personalize for each recipient. 
When you write a letter, it's a good idea to be aware of the audience you that want to reach. Business letters are more effective when they follow a more formal structure. Letters to friends can be less formal in tone.