Letter - Informal
Letter writing still has a sentimentality about it that surpasses all other forms of communication. An informal letter is a letter to a close friend or acquaintance. These letters are very spontaneous, informal and usually related to personal matters.
An informal letter gives us an opportunity to demonstrate informal language skills. There are as such no formal rules about how to write an informal letter; however, there is certainly a conventional way of going about it. This means that the basics like the address, date, salutation, language and conclusion indeed stay the key components of a letter. It is just that when writing an informal letter, one can be informal in the tone, style and voice of the letter. As an informal letter adds personal touch to one’s thoughts and ideas, it is best to keep it friendly and conversational.