Letter Writing A letter is a written message that can be handwritten or printed on paper. It is usually sent to the recipient via mail or post in an envelope, although this is not a requirement as such. Any such message that is transferred via post is a letter, a written conversation between two parties. However, today letters can be sent via email, that is, they are no longer handwritten. Why would I write a letter? Job Application: Formal or business-related letters could include job applications such as a resume and cover letter. Keeping in touch with older relatives: Letter writing can be a lovely way to keep in touch with people who remember a time when letter writing was more popular. Thank you letter: A thank you letter expresses gratitude of doing something or having received something.