When writing the date in a formal letter, you should write it in full with no abbreviations, for example, "December 12, 2019. The heading includes the date the letter is written.If you do not use letterhead stationery, you need to include your address above the date. Learn how to write effective resumes and cover letters, view sample resumes and cover letters, and get tips for completing job applications. In a formal letter, you would spell out the month in letters, and write the day and year in numbers as shown below. Write out the month in full, and avoid using abbreviations or numerical formats. For example, the date may look like "31 January 2019" or "January 31, 2019. Depending which format you are using for your letter, either left justify the date or tab to the center point and type the date. When writing a letter using simplified style form, put the date on the left. Letters are time capsules after all.