Using Classic Outlook on Windows for personal email, calendar, and contact management
Hi Michael,
This is happening because there are two different Outlooks now.
In the new Outlook for Windows, the Quick Access Toolbar and the Ruler feature are not available, so the instructions you found will not work there. Microsoft's own article notes that Ruler is not supported in the new Outlook.
Open Outlook and look at the top right. If you see the New Outlook toggle, turn it off and choose Switch back to classic Outlook.
Once classic Outlook opens, start a new message so the compose window is in its own window. In that message window, open the Quick Access Toolbar menu at the far right of the ribbon, choose More Commands, set Choose commands from to Commands Not in the Ribbon, select Ruler, choose Add, then OK.
You will now have a Ruler button.
If you do not see the Quick Access Toolbar at all in classic Outlook, turn it on from the ribbon's drop-down menu using Show Quick Access Toolbar, or via File > Options > Quick Access Toolbar > Show Quick Access Toolbar. After that, add the Ruler as described above.
Try those steps and you should be able to view the ruler while composing. If anything behaves differently on your screen, tell me which Outlook you are on and I will adjust the steps for you.