They were typed and handwritten; sophisticated and simple; written on letterhead from captains of industry and on lined paper from schoolchildren.
Use a technique that suits you, e. g. write summaries, paraphrases or quotations on note cards, or separate sheets of lined paper.
It was lined paper, torn out of a notebook, and cut smooth.
To take notes effectively, choose a sheet of loose, clean, lined paper, preferably college-ruled.