a cookie recipe ask for 2 cups of flour and a pinch of salt. what flour do i use

If not specified, use all purpose flour. Anyhow, most cookie recipes ask for all purpose flour. Very few might ask for i.e. Pastry flour.

An all purpose flour would be the best way to go. It would be helpful to know a little more about the specific recipe in order for us to be able to give a more detailed advice, but you won't go wrong with an all purpose flour. The remainder of the ingredients and their proportions will define the final texture for the most part. Not all cookies need a leavening agent.

Can you provide the recipe?