The principal kind of paper used in Chinese painting is Xuan paper, commonly known as rice paper. For painting, there is no such thing as paper made from rice. Commonly, paper made from rice is used for wrapping candies and confectioneries and is totally edible. Paper used for Chinese painting is often referred to as "rice paper" when, in fact, it may be made from a number of different kinds of fibres. Examples include: Xuan papers, mulberry papers and cotton papers - each with their own unique make-up. For simplicity sake, we will refer to these many kinds of paper as "rice paper."
Some papers are treated with certain chemicals or substances that impart a specific behaviour to the paper. These papers are labelled as "sized." For example, paper coated with alum is less absorbent of the paints applied to them. The paint sits on the surface of the paper and tends not to bleed.
Another type of paper has alum mixed into the paper pulp in the papermaking process so that the alum is distributed uniformly throughout the paper itself. This allows the paper to absorb a certain amount of applied paint but hampers bleeding.
This is a different type of sizing and its property can be exploited in certain situations. This range of absorbency gives you the choice of different papers for different applications and is very open to artists' preferences and styles.
Typically, for beginners, I recommend Xuan paper. It is challenging but, once mastered, you will then have an easier time of making the transition to other types of rice paper.