How can I get my Mac to export reports into excel automatically.

You will need to  change your settings to open files. 

1. On your Mac, click the finder icon in the Dock to open a finder window. 
2. Select the file, then choose File > Get info.
3. You can also Control-click the file, then choose Get Info. 
4. In the Info window, click the disclosure triangle next to open with
5. Click the pop-up menu, then choose the app. 
6. To open all files of this type with this app, click Change All