Answer:

Definition of Formal Letters

A formal letter is any letter written in the professional LANGUAGE, with a prescribed format for a formal purpose, i.e. it can be a recommendation letter, enquiry letter, complaint letter, cover letter and so on. All business letters are formal, but vice VERSA is not possible. Such letters are used for a variety of reasons like a formal invitation, PROPOSAL, reference, making a complaint or inquiry, applying for a job. While writing a formal letter one should keep in mind the following things:

It should be in specified format.

It should avoid the use of unnecessary words.

It should be straight to the point.

It should be relevant and objective.

It should be complex and thorough.

It should be polite, even if it is a complaint letter.

It should be free from any mistakes, i.e. grammatical or spelling.

There are three types of formal letters, i.e. business letters, letters for outlining civic problems and job applications.

Definition of Informal Letters

An informal letter is a letter written to someone; we know FAIRLY well. The letter can be used for some reasons like conveying message, news, giving advice, congratulate recipient, request information, asking questions, etc. It is a personal letter, written to whom you are familiar with, like friends, siblings, parents or any other closed one. There is no specific format prescribed for writing this letter.

While writing an informal letter, one can afford to be friendly, and make use personal or emotional tone. Slang or colloquial TERMS, codes, abbreviations, etc. can also be used at the time of writing it, depending on the familiarity with the recipient