Tableau - How to publish a view, workbook or dashboard with last refreshed date and time
Open the workbook that contains the dashboard in Tableau Desktop, then navigate to the sheet for which you want to display the time of the last data refresh.
- Select Worksheet > Show Title.
- Double-click the title.
- In the Edit Title dialog box, select Insert > Data Update Time, and then click OK.
The Data Update Time value depends on the type of connection:
- Extract-based connections display the last time the extract was refreshed.
- Live database connections display the last time the data source was refreshed.
- Live file-based connections display the last time the file was updated.
This is from the Tableau community page. Please see https://community.tableau.com/thread/212116 for additional information.