Open a document, then choose Pages > Settings (from the Pages menu at the top of your screen).
Click Rulers.
Select the checkbox next to “Show vertical ruler whenever rulers are shown.”
Go to the Pages app on your Mac.
Open a document, then choose Pages > Settings (from the Pages menu at the top of your screen), then click Rulers at the top of the settings window.
Click the Ruler Units pop-up menu, then choose an increment (Points, Centimeters, or Inches).
To show the ruler marks as a percentage of the page, select the “Display the ruler units as percentage” checkbox.
You can place 0 (zero) at the center of the ruler so that ruler units increase to the left and right.
Go to the Pages app Use alignment guides in Pages on Mac