To determine which version of Excel you have, you can follow these steps:

1. Open any Excel file.
2. Click on the "File" tab in the top left corner.
3. Select "Account" or "Help" from the left-hand menu.
4. Under "Product Information" or "About Excel," youll find your Excel product name and version number.

On newer editions of Excel, you can also find version details by opening a document and clicking File > Account > About Excel. On a Mac, you can click Excel, then About Excel to find the version number. Additionally, when you click on the Microsoft Excel icon on your computer, it displays the name of the application that you are using and the version that you are using.