A justification letter typically begins with an introductory statement explaining what the letter writer is requesting from the person or organization the letter is addressed to. It also should include the cost of the request and the benefits to the company of the request being accepted along with other pertinent data.
Letters of justification are most often used to formally request funding for a potential project or venture within an organization, but they can also be used in a variety of other ways. These include a means for negotiating a salary raise or promotion, a request for patient coverage by health care providers, and a method of extending or changing a contract between multiple parties.
When considering the format, it is important to include any and all relevant data to support the purpose of the letter including the cost of the request, even if it's only an estimate, and any previous successes for similar work that might help to sway the letter recipient towards granting the request. A tone of courteous professionalism should be maintained at all times. A justification letter is not a demand; it is a formal request. This is an important distinction to be made, as a request in a justification letters could just as easily be denied as accepted.