Hi there, @susan_new.

Thanks for reaching out to the Community today. Allow me to join this conversation and provide you with some details about exporting an excel file in QuickBooks Desktop.

Office 365 should work since it is compatible with the supported versions of QuickBooks. If you only have the option is to export to a CSV file, this can be caused by the following reasons:

•    Excel is not installed on your computer.
•    It's installed across a network.
•    The local Excel installation is damaged.

To single this issue out, you'll need to toggle the UAC in Windows.

Let me guide you how:

1. Turn off UAC by selecting the Windows Start button.
2. Go to User Account Control Settings by typing Change User Account Control Settings, then press Enter or typing Control panel and press Enter. Then, select User Accounts and click Change User Account Control Settings.
3. Move the slider to Never Notify and click OK.
4. Restart your computer and open QuickBooks.
5. Go to Reports and select a report you want to export.
6. Click the Export button.

Here's a great article that will provide you more details on how to perform the process: Export option for Excel is grayed out.

That should do it.

Please give this a try and let me know how it goes. If you have any questions, leave a reply below. I’ll be here to answer them for you. Thank you for reaching out and take care!