Pages

Use rulers in Pages on Mac
Pages provides horizontal and vertical rulers to help you lay out text and objects in your document. For word processing documents like a letter or report, you need to turn on the vertical ruler in Pages settings. The vertical ruler is always available for page layout documents.
You can set the ruler to use different increments (points, inches, centimetres), or show the tick marks as percentages. You can also place 0 (zero) at the centre of the ruler, which can be useful if you’re designing a page layout document.
Tip: You can also use the ruler to set margins and tab stops, and you can drag alignment guides from the ruler to the page.