Eventually, You'll have to purchase paper. Bristol paper is commonly employed by illustrators as it's very thick and has a smooth complete. Watercolour paper is yet another sensible choice as it will never buckle for those who use loads of ink. You can even use illustration board and mixed media https://howtodrawwithinkpens25825.blogdigy.com/the-best-side-of-ink-drawing-for-beginners-56142924