Due to significant code changes in the Joomla! core, the Visforms field type date, as implemented in Visforms up to version 3.8.21, is broken.
In the field configuration, setting the selected date format for "Initial value" for the date field does not work. Further on the layout of the calendar, that is used for setting this "Initial value" looks broken.
In front end, there is a javascript error "Calender.setup is not a function", with any form, that contains fields of type date. If you click on the calendar icon, nothing happens. This javascript error may result in disabled submit and reset buttons as well, depending on your Visforms versions.
In order to fix the problem you have to update your Visforms installation to the latest Visforms versions (currentliy 3.8.22), which contains the required fixes for this bug. The update should be displayed in the update manager of your website. It is compatible with older Joomla! versions.