What is the exact format for writing letters and e-mails in English? What is the difference between the following three formats?

Letter format is more strict and complex, while e-mail is a simplified version of a letter. The main difference is that a letter begins with specific contact information for the writer and recipient, while an email begins directly with the content. All three are email formats, but the difference lies in the closing words - yours, none, your friend.

Yours can be addressed to someone more intimate, such as a relative, lover, or close friend.

None, generally can be used in simple conversations (not formal occasions) like between people of the same age.

your friend on the other hand is between friends.

Generally used formally: sincerely, regards, or kindly best, warm regards

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