When choosing a pen, beginners should choose a double-stranded brush.
As for the pen diameter, it is only the ink storage capacity. In terms of size, if it is about 3 cm, choose a small pen, within 3 cm of the front. For words smaller than 6 cm, choose the pen in the middle, and the front is smaller than 6 cm.
In short, this is only relative. Because everyone has different pen habits, you can also choose the size of the pen according to your own pen habits. But generally speaking, there is nothing wrong with a slightly larger pen, and the fine print is thicker, but it can't be small, so as not to damage the pen when writing.