Templates have many faces and styles. Some are specific to an industry. Use these templates as guides in drafting your own letter.
Letters for every situation that may arise regarding your businesses cash flows, such as an overdue account letter can quickly be put together and sent out if you have a standard letter ready. You will also need forms and letters to assist with your customer relationships. You should have a standard 'client details' form ready for each customer's details and preferences to be filed. You also need customer feedback surveys and a series of letters welcoming new customers and dealing with various other complaints and issues.