a letter is a written form of communication.
the first thing I think when i think of a letter is a stamp, envelope and something to read.
a letter is categorized into personal and impersonal(which is formal)
reasons for writing a letter;
- asking for a job
- well wishing
- inquiry on formal issues
- resigning
- greetings
- love address
- formal complaints
basiclly a letter is a form of communication that can be elaborate,funny,open as wished when sent to friends and families but can be formal,authorized and improvised when it's impersonal and is sent to a titled person.