Hi again, Ingegerd! WPForms support reached back out to let me know that there is an option to use custom code to create your preferred date format.

Here are the instructions: https://wpforms.com/developers/how-to-create-additional-formats-for-the-date-field/

Hi Ingegerd, thanks for the note! I checked with WPForms support, and they said you’re right that yyyy-mm-dd isn’t available. However, dd-mm-yyyy, another commmon date format in Europe, is an option in WPForms. Instructions for changing to that format are here: https://wpforms.com/docs/how-to-customize-the-date-time-field-in-wpforms/#date-format

They also said they would log your comment as a feature request for future improvements.

Hope this helps!