In Tableau how to change the calender date format in Parameter?? If anyone knows please help!!!
While creating the parameter or while editing, the option to change display type is available, as seen below. The available custom format options can be found on Tableau's site here.
If you are thinking about the format of dates across your entire dataset, try the following:
Data Menu > [Select Datasource] > Date Properties...
You will get a dialog like this which can adjust all dates: