Lined paper is paper which has been printed with lines with ink so people can write on it. It is popularly used in education.
Can guinea pigs eat lined paper?
If they are fed any type of substance, guinea pigs will look to eat it.
This includes lined paper which is used for a lot of people who like to use it.
If the lined paper is chewed at all, it would be fine for guinea pigs to chew and eat and they will be fine.
If you are worried about the ink, it is harmless to piggies and is not poisonous at all.