Drawing tablets are a great tool for aspiring illustrators because artwork is becoming more and more digital over time. While it is still great to learn and use traditional aspects of drawing, learning to use a drawing tablet is well worth the effort.
All drawing tablets come with a stylus that works exactly like a pencil, except on a tablet. For lower priced tablets the hard part is practing drawing on the tablet while looking at a computer screen and learning how to coordinate your hand movements. Higher end tablets have a screen that you can directly draw on and see your artwork as you are drawing which are similar to some laptops but are more accurate and try to match actual drawing. Drawing tablets are pressure sensitive and are close to drawing traditionally. They also work well with artist software programs like Illustrator, Photoshop, etc.
As to figuring out which kind of drawing tablet would be best for you, that depends on a few factors. Price is a big one, with higher end tablets being very expensive and more basic models costing a lot less. The basic models are usually very small and come with a stylus and a few replacement tips, while higher end models have the screen that you can physically draw on and are much larger. If you are just starting out, a cheaper smaller alternative might be best and you can invest in a better one later on. Hopefully this gave some insight to illustrators looking into new ways to approach their artwork!