Web Developer

You should have a knowledge in various web developing languages like PHP, Magento and WordPress

Here are following important facts why we choose web development for best career.
1. It’s much simpler to do and learn
2. Creative & Expanding field
3. Best career opportunity
4. Attractive salary package with high growth
5. Work from where you want
6. Provide opportunity to settle abroad
7. Be your own boss
8. Bright future scope

First you need to find out, what kind of web developer you need to be.
I've found this article useful which gonna help you in sorting out this : http://blog.teamtreehouse.com/what-types-of-developer-are-there

I would like to answer the question you should have a skills about several programming languages like as php, Magento, java, etc,

You can read latest article http://seo-advanced-techniques.blogspot.com/2018/07/web-design-trends-2018-what-will-make-Effect-this-year.html

HTH!

Regards,
Daniel

You should know some web languages like C, Java, PHP etc. Apart from this, you must know some CMS like Wordpress, Drupal, joomla, Magento etc.
Above all, you'll have to be analytical and possess technical skills required for web development.