A very excellent and free CW Trainer is available from Ray Goff G4FON at his website.
http://www.g4fon.net
At LCWO you can learn Morse telegraphy (CW) online in your browser. You don’t need to install a program on your computer, and you always have your personal settings available, from any computer on the globe with an internet connection. You can also easily track your progress by means of different statistical functions.
https://lcwo.net/
CW is an abbreviation for Continuous Wave,
describing how Morse code is most often transmitted.
A transmitter is simply keyed on and off and
a tone is sent to the receivers and heard as a beep.
Morse code is popular among amateur radio operator, and
is a method of transmitting information as a series of tones that
can be directly understood by a listener without special equipment.
The International Morse Code encodes the alphabet and
numerals as sequences of short and long beeps called
“dots” and “dashes”,or “dits” and “dahs”.
Each letter or numeral is represented by a unique sequence of dots and dashes. The code was designed so that the length of each character varies approximately inversely to its frequency of occurrence in English. The most common letter in English, the letter “E”, has the shortest code, a single dot.
Some interesting links:
Perhaps some of the best CW Operators in the world may be found in the group below.
Listening to their code is an excellent way of improving your receiving skills
after learning code with the Trainer.
Gateway Amateur Radio Club 