While Morse code is not required to get your license, it is a popular mode and a lot of fun!

You can find a lot of study aids online or you can purchase a system.  There are apps aplenty, but there is no one fool proof way to learn "the code"  And you must committ to what ever you choose.

 

https://morsedx.com/

https://skilman.com/

https://www.cq2k.com/index.html

http://www.arrl.org/shop/Your-Introduction-to-Morse-Code-audio-CDs

https://www.w5yi.org/catalog.php?sort=17

https://cwops.org/cw-academy/

http://www.hamwhisperer.com/p/morse-code-course.html

The ARRL maintains an code practice schedule  - it changes occaisionally so we have provided a link below

http://www.arrl.org/code-practice-qst-source

T
hey also offer some code practice files to listen to 

http://www.arrl.org/code-practice-files