To format date in Crystal Report, the field must be date type. If the field is an integer and you want to convert this into day please see convert int to date in Crystal Report
To format date in Crystal Report, simply click on the field name, right click, format field. Make sure to select “date and time” tab. Select the proper format you want to show in. If the field is not recognized as date by Crystal, “date and time” will not be shown.