Drawing digitally needs three things: an appropriate drawing tablet like Wacom bamboo, a study guide, and a program. Both a tablet and a program are easy to find. Just search google for appropriate programs and check out Amazon for the tablet
Things get harder when talking about study guide. Although it is easy to plug everything and begin to draw, the first results may be less than professional. To improve that, look for a drawing course for beginners. Digital or traditional it does not matter, because it is the principles you need to learn.
Follow the exercises, like lines weight, color theory, composition and painting in greys. This will enable you to start thinking about what images could look like and how to get the basic effects. In addition, watch YouTube drawing videos or channels and try the same image yourself. If you have some money, buy one or two good drawing books.
The difficult part of drawing on tablets is learning to watch the screen instead of your hand. Once the brain is trained to ignore such dis-connect, you can focus on the drawing process. Sketching regularly with a pencil enables an individual to learn about the line, form, tone and composition. After some months, you will be a self-taught digital artist.
References
https://www.quora.com/How-do-I-start-out-drawing-digital-art-with-no-drawing-expierence