If for any reason you prefer not to use the built-in ticket form or the integration with Ninja Forms, there is a way to use your preferred form creation plugin and import tickets from it by using the email piping add-on.
To do so, instruct your contact form to send emails to the email address you have configured to import emails from in the email piping settings. Make sure to populate the from name & email with the details of the user submitting the ticket, so they can be imported correctly in the ticket details.
If you are using custom fields, it is possible to populate them by setting additional email headers. Please check if your contact form plugin supports that functionality.
The headers must use the “x-wphd-” prefix, followed by the internal name of the custom field. If for example, the internal name of the custom field is “department”, then the headers should be sent as such:
x-wphd-department: [content]