An informal letter is a type of letter that is written in a personal and casual manner, usually to a family member, close acquaintance, or friend. The language used in an informal letter is conversational and personal, similar to a friendly chat. When writing an informal letter, it is important to include the senders address, date, greeting/salutation, introduction, body of the letter, conclusion, and signature. Unlike formal letters, informal letters do not need to state something specific and can include a variety of topics. They can also include colloquial expressions and are meant to convey personal thoughts and feelings. Informal letters are a way to let friends or family know about what is going on in your life and to convey your regards.
In summary, an informal letter is a personal and casual form of communication, often used to share personal news, thoughts, and feelings with friends or family members. It follows a less rigid structure compared to formal letters and allows for a conversational and friendly tone.