MERN stack stands for MongoDB, Express JS, React JS, and Node JS. I will develop websites in the MERN stack for any individual/ organization. The front-end of MERN stack sites is made with React JS, and Back-end is made with Express JS. All data of a MERN stack sited is backed up in MongoDB database. MERN stack websites are usually very popular and first because React JS is a very organized and efficient web framework which usually made SPA/ Single Page Application which doesn't take reload while browsing from one page to another. That's why in today's era MERN Stack is one of the top trends in web development. 

The most common features that I developed in a website are:

1) Decent Looking UI

2) Dashboard for different users (admin, general user, buyer, seller, etc.)

3) user authentication system (sign in/ sign out) and many more functionalities.