The document provides instructions for writing informal and formal letters in 7 steps. For informal letters, it recommends including a salutation like "Hey!", starting the letter by thanking the recipient or apologizing for not writing sooner, including 1-2 short paragraphs in the body to answer any information or ask questions, and ending with a closing line and complimentary close like "Love" or "Cheers!". For formal letters, it advises including a formal salutation like "Dear Mr./Mrs.", stating the reason for writing in 1 paragraph, including 2 paragraphs in the body to answer any information, ending by expressing what is wanted in return and including contact details, and closing with a complimentary close like "Yours faithfully".