Use the following macro to add the full path or URL for a workbook to the left side of the footer:

Sub UpdateFooter()
ActiveSheet.PageSetup.LeftFooter = ActiveWorkbook.FullName
End Sub

To use this macro, save the workbook and click the worksheet where you want to add the footer before running the macro.

To add the path or URL to the right side of the footer, the left side of the header, or the right side of the header, change LeftFooter in the macro to RightFooter, LeftHeader, or RightHeader, respectively.