PDF2XL has a Command Line Interface which allows you to control several of the application's parameters.
You can look up the available CLI commands, and view CLI Examples, to learn how to use this feature.
If the command line contains errors, PDF2XL will NOT start, and an error code will be returned.
Note that you can also open files in PDF2XL directly from the command line by specifying their names in the command line (see example here).

If you need better control of PDF2XL from the command line (for example, running a conversion without any user interaction, or specifying the document's layout from the get-go), you can use PDF2XL CLI instead of PDF2XL.