If you work from multiple locations, you can choose to specify which location you consulted at on the patient's invoice. To enable this functionality you will to go to Business Setup -> Invoice Settings -> Location -> Toggle to YES -> Save.

Now, when you are in an invoice you will see the following pop up that location needs to be selected:

You can specify the location within the invoice details box on the right by selecting the dropdown menu across from Location:

All your locations will appear to select. Once a location has been selected, the pop up to select a location will disappear.