If a person is writing a formal letter, then his letter should contain some of the following elements: Proper greetings/salutations and reason for writing etc.
<h3>What is Letter Writing?</h3>
A letter writing defined as a use of letters to convey opinions or feelings to anyone who live far away from us. The letter writing is divided into two parts Informal and Formal letter.
In case of letter writing, people need to write the proper address of sender, greetings and the main thing: the reason of writing this letter.
According to the Newsela article "How You Can Make a Solar Oven To Cook with a Pizza Box.", the author's purpose in mentioning that solar energy is cheap is to
