Thank you. The below worked.

Paste the following code into the new module:Public Function ModDate()ModDate = Format(FileDateTime(ThisWorkbook.FullName), “m/d/yy h:n ampm”)End Function
Before saving your module, make sure to save your Excel file as Excel Macro-Enabled Workbook
Save your module
Return to your Excel worksheet
Paste the following code into the cell where you want to display the last modification time: =ModDate()