One line at the top, one at the bottom
Both lines are centred, drawn in grey Helvetica, and share a single font size between 6 and 16 points.
You can fill in either field or both, and whatever you enter is repeated on every page. The two lines sit a fixed distance from the top and bottom edges. There is no left or right alignment, no colour choice, and no way to vary the text between odd and even pages, so this is a tool for a consistent running line rather than a full layout system.