There are many excellent online resources for introduction to HTML (hypertext markup language) that will enable you to learn the code required to generate Web pages. The various tutorials posted here require the user to have a basic understanding of HTML code.

Six very good starting sites with an abundance of well organized information and referrals to others are:
Offering HTML 101, a 10 week online course in the fundamentals. Many referrals to other resources.
A super site that's easy to navigate with oodles of Web design info. This site sponsored by the National Cable Television Association and Tech Corps is an online resource you will find to be a priceless resource. Now availble in both English and Spanish. 
For a fee, please consider a subscription to the tutorial of your choice. These will serve as a springboard or starting place for an enjoyable career in web development and/or coding apps.

I strongly suggest you employ the GOOGLE search engine to seek out specific information on any Web feature of interest.