Proofreading involves checking a document for spelling and format errors, as well as reviewing the document for grammatical errors.
A formal letter is a professional letter, which is written in formal language, in a specified format, and in the stipulated format. This letter is mostly used for professional communication. Informal Letter. An informal letter is a personal letter, which is written in a friendly way to someone we are familiar with.
To learn more about informal letter, refer
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