These are several sites where you can go to learn more about coding:

www.code.org

https://scratch.mit.edu/about/

https://www.tynker.com/hour-of-code/

https://www.madewithcode.com/

http://codecombat.com/

This is an article from Common Sense Media with highly rated tools for learning how to code for students of all ages.

https://www.commonsensemedia.org/blog/cool-tools-to-help-kids-learn-to-code?utm_source=091115+Ages+7-12&utm_medium=email&utm_campaign=weekly

This is a source to learn how to create apps for Android devices: http://www.appinventor.org/