Pages
Use alignment guides in Pages on Mac
Use alignment and spacing guides to help you place objects precisely. When guides are turned on, they appear as you drag an object on a page in alignment with, or equidistant to, another object. You can turn the guides off and on as needed.
You can also add your own horizontal or vertical alignment guides and place them anywhere on a page. These persistent alignment guides don’t appear and disappear as you drag objects, but remain visible while you’re working.
Tip: You can add a button to the toolbar to show and hide guides.