Question

formation of informal letters and formal also??

Answer 1

A formal letter is one, written in formal language, in the stipulated format, for official purpose. ... On the other hand, informal letters are used for casual or personal communication. There is a manner prescribed for writing formal letters. As opposed to informal communication, which does not follow any format

An informal letter is a letter that is written in a personal fashion. You can write them to relatives or friends, but also to anyone with whom you have a non-professional relationship, although this doesn't exclude business partners or workers with whom you're friendly