Overleaf is an online collaborative writing and publishing platform designed primarily for creating documents using LaTeX, a typesetting system commonly used for academic and scientific papers. It allows users to write, edit, and compile documents in real-time, making it easy for multiple authors to work together from different locations. The platform offers a variety of templates for different types of documents, including articles, theses, and presentations. Users can access their projects from any device with internet connectivity, and it provides features like version control, commenting, and integration with reference management tools, enhancing the writing and editing process.