View Multiple Workbooks in Excel
If you want to view multiple Excel workbooks at the same time, execute the following steps.
1. First, open two or more workbooks.
2. On the View tab, in the Window group, click Arrange All.
3. Select the desired arrange setting. For example, click Horizontal.
4. Click OK.
5. On the View tab, in the Window group, click View Side by Side (by default, Synchronous Scrolling is activated) to scroll both workbooks at the same time.