'mailto' is the default action for HTML forms. However for this to work the browser needs to be configured to use the default email application.
If there is no default email client then 'mailto' will not work, because the browser does not know how to send emails without it.
You can read the following internet article for more details:
https://webdesign.about.com/cs/forms/a/ ... obroke.htm
As you may already have guessed, using 'mailto' for form processing is not very reliable, so it's better to use some kind of server side script (like PHP) to collect the data.
WYSIWYG Web Builder has a built-in PHP form processor script. It performs most basic form processing tasks like sending emails, uploading files or writing data to a database.
Related tutorials:
https://www.wysiwygwebbuilder.com/forms.html
https://www.wysiwygwebbuilder.com/form_wizard.html