In Excel, if you want to compare two tabs the same file, you can duplicate the window. It is possible in all applications.
To compare and put 2 tabs of the same workbook side by side, you need to create a new window for this file.
On the View menu, click New Window.
You get 2 independent windows that you can put side by side. You can view different tabs.
Any changes will affect both views. This is just a display duplication and not the duplication of the file itself.
The different windows are numbered, a sign that the window has been duplicated.
This feature exists in all Microsoft 365 apps.
