I never actually tried learning how to write kanji before, because I always thought it was too difficult and not really that useful to me.
But now, since I’m serious as **** about learning Japanese, I decided that it’s time to learn how to write them as well
I tried about a dozen (no joke) different programs for windows and apps for my phone and all of them were total crap, until a friend of mine suggested me to try a particular app called 小学生手書き漢字ドリル.
The app is obviously in Japanese and is intended for Japanese school children. But it works like magic! In just an hour I learned to understand everything about stroke order and how to write kanji properly, plus how to write about 50 kanji

It lets you draw and then checks if you did it correctly, including stroke order and all other jazz. If you don’t know how to write a particular kanji it includes a stroke diagram for each.
Plus it lets you test your knowledge in a simulated test/exam.
Here are the links to google play store, but there is also an iPhone version as well.
https://play.google.com/store/apps/details?id=jp.co.gakkonet.quizninjategakikanjidrill
https://play.google.com/store/apps/details?id=jp.co.gakkonet.quizninjakanjidx
And there you have it

–Edit
Here are App Store links, say thanks to gregorspv

https://itunes.apple.com/jp/app/xiao-xue-sheng-shou-shuki/id492090392?mt=8
https://itunes.apple.com/jp/app/xiao-xue-sheng-shou-shuki/id575809449?mt=8