Place the date at the top of the letter, usually aligned to the left or right
Use a formal date format such as 12 March 2026 or March 12, 2026
Write the month in full instead of using abbreviations
Use Arabic numerals for the day and year
Include the full year
Avoid informal formats such as 12/03/26 unless required by local convention
Keep the date consistent with the style used in the rest of the letter
In British formal letters, use 12 March 2026
In American formal letters, use March 12, 2026