The form is configured in qa-include/pages/messages, starting around this line.
The form is output using various functions in qa-theme-base.php, for example form_fields here.
Welcome to the Q&A site for Question2Answer.
If you have a question about Q2A, please ask here, in English.
To report a bug, please create a new issue on Github or ask a question here with the bug tag.
If you just want to try Q2A, please use the demo site.
April 20, 2021: Q2A 1.8.6 released!