How do you write out formal time?

To write out formal time, use the 12-hour format with "AM" or "PM" to specify the time of day. For example, instead of writing "3:00," you would write "three o'clock in the afternoon" or "three o'clock in the morning." In formal contexts, it's also common to use "noon" for 12:00 PM and "midnight" for 12:00 AM. Always ensure to maintain clarity and consistency in your writing.