Website development is the art of building pages that can be rendered nicely on a web browser. It also involves building software applications that can be run on a server and displayed on web browsers e.t.c. Web browsers that can be used to render website applications include, Mozilla Firefox, Google Chrome or Microsoft Edge among many other web browsers out there.
There are different levels of web development:
Front End Web Development
This is the category where most “web developers" reside as it is usually the initial stage one gets into while starting out as a web developer. It is relatively simple to play around here than at the backend but it can also get complicated when building intuitive but large web applications with lots of data.
Back End Web Development
At the backend, server rendering of scripts takes place as well as data storage and manipulation. Technologies like PHP, relational and non-relational databases also rest at the backend and dealing with them while building a web application is mostly considered a backend web development task. If you are looking to become a data analysis expert with web apps you can learn Python.
Writing a basic web application is rapidly becoming the standard of “web development", as it involves a good amount of both frontend and backend knowledge. Such tasks can also be achieved using frameworks like React, Angular and Vue at the frontend and Laravel, CodeIgniter, Django, Flask and Spring at the backend.
Developing interesting apps, e.g. using WebGL is a specialized category where other programing disciplines (graphics in this case) intersect with web development.
Writing complex web apps is where it gets to be more of a specialized profession, where UI knowledge and patterns need to be at a certain degree and also a need for actual architectural design.
In conclusion, a huge part of web development is to keep learning, which implies reading up on programming concepts like MVC, using new frameworks, libraries and SDK's as well as new ways of implementing ideas. Always keep check of what your peers and industry leaders are doing. If you are a person who gets bored with routine work but gets excited upon meeting new challenges, then web development is for you as the career involves problem-solving and challenge addressing. In the long run, a web developer's ability to quickly and deeply understand new ideas grows infinitely. I also want to note that Web development's detriment is its nature of sitting down for long hours, you can quickly become unhealthy if you do not schedule some time to exercise.