Grammarly is an AI-powered writing assistance tool designed to enhance users' writing by providing real-time grammar, spelling, punctuation, and style checks. It integrates seamlessly with over 500,000 apps and websites, including Word, Gmail, Google Docs, and LinkedIn. In addition to its core functionalities, Grammarly offers a plagiarism checker, citation generator, and essay checker, making it a comprehensive solution for writers, students, and professionals looking to produce error-free and polished content.