How and Where to View Invoice As Client

Hi everyone.

I'm new to setting up WHMCS. The other day I happened across a command that allowed me as admin to view an invoice as the client. I thought it was a useful feature, and I need to use it again... but I can't seem to locate the command. I guess I'm just overwhelmed right now with all of the new information.

Where do I view the invoice as client through the admin panel?

Thanks,
Buck