Sololearn is a great application for use on your phone, it is flexible and easy to use, you can learn how to create a website by learning the basic code language you need i.e Html, Css, Javascript.
Sololearn also has other scripting and programming languages such as C++, Ruby, Swift Fundamentals, Python 3, Php, MySQL, jQuery.
There are exercises to access what you have learnt at the end of each lesson.
You will also earn a certificate upon the completion of each course.
There is also a coding playground for you to practice and test run your codes.
It is available for download on Google Playstore.