You can customize the appearance of the InputDate and its drop-down calendar using CSS. You can also use the calendar's formatItem event to customize the appearance of specific dates in the drop-down calendar.
You can customize the icon shown in the drop-down button by changing the InputDate's controlTemplate property, or by using code to change the control content. The first option would affect all InputDate controls in the application; the second would affect only a single control.
You can also customize the format used to display the current month/year in the drop-down Calendar by changing the Globalization's standard 'y' format, or by using code to change the control content. Again, the first option would affect all InputDate and Calendar controls in the application; the second would affect only a single control.
For example, the InputDate below applies custom styles to weekends and holidays. Also it uses custom Globalization's 'y' format, and the InputDate's controlTemplate property is changed to change InpuDate icon to a calendar instead of a down arrow.