1. Touching is enough for beginners, but it is really easy to spread.
If you have money, you can buy one. COPIC has replacement pens and supplementary ink, which can reduce the comprehensive use cost.
3. High-end products can use American Sanfu Prima. Prima, the American Sanfu, is quite good, with two round heads and two cut faces. It's easy to use when you get used to it.
Hand-drawn tools commonly used in industrial design, such as pencils and pens, are sold in general art stores.
Computer hand-drawing, Photoshop, Painter, Alias Studiotools, coreDraw and a computer hand-drawing board are also necessary.