Dear …
Thank you for allowing __ (company name) __ the opportunity to be of service to you for your __(type needs)__. We wanted to send you this letter to express to you how much we appreciated your business.
We know that today, consumers generally have a wide selection of choice out there. It is therefore, a privilege for to us to have been chosen as your __ (type of product/service) __ provider. We strive to ensure our customers are happy with the __(type of service/jobs/projects/etc.)__ we do for them. Our commitment is to consistently provide first rate service and we hope that you found both our service and workmanship to have been top quality.
We offer a full range of __ (type of products/services) __ and ask that you keep us in mind for any future __(type of)__ __(projects/needs)__ that you may have. Thank you again, for choosing __ (name of company) __. We hope that you enjoy your new __(type of completed project)__.
Sincerely,