Question

If you’re asked to list for things can the way of your listing be vertical or horizon.

Answer 1

this is the quesion
List four things to look for when you’re proofreading?

Answer 2

You could list it in any form, however, 99 percent of lists I make or use are in vertical form, I guess I learned to make outlines and lists in vertical forms a long time ago.
Make the lists vertical.

as in ...
correct spelling
correct puncuation
complete sentences
main thoughts developed