In Outlook, how can I split the same email on the same monitor?

I need read distant parts of a lengthy email chain simultaneously.

Thank you for asking this question. I’m forced to use Outlook at work, and by finding this answer I now learned something that will come in handy.

1. Double-click the message to open it in a separate window.
2. From the File tab, select Options
3. Select Quick Access Toolbar
4. From the drop-down Choose commands from:, select the entry Commands Not in the Ribbon
5. Scroll down and select Split, and click Add >>
6. Click OK

You now have an icon in the Quick Access Toolbar that will split the message window similar to Word and Excel.

Source: https://www.bettercloud.com/monitor/the-academy/split-message-window-outlook/

One option would be to copy the entire mail in to a Word document, and use the View → Split option in Word.

I couldn't find a Split option in Outlook, but since you have multiple monitors, you could configure them below each other, rather than next to each other. To do that, right click on the desktop, select Screen resolution to open the configuration screen. Drag the monitors to the desired locations (as 1 and 2 in the screenshot below). Now you can increase the height of the mail window by dragging, or double clicking its top edge (Maximizing it will only occupy a single screen).

Mouse movement may be awkward when moving from one window to the other though.