This document provides an overview of the grammar checking tool Grammarly. It describes Grammarly's free features such as spelling, grammar, and punctuation checking. The premium version offers additional style checks, vocabulary enhancement, and plagiarism detection. Grammarly can be accessed through browser extensions, online applications, and desktop applications. It is suited for students, professionals, writers, and researchers to improve writing skills and detect errors. While it effectively finds most grammar mistakes, the premium version is costly and some features are not available on Mac. Alternatives to Grammarly are also listed.