You just have to upload an empty .htaccess file to your server.
Once uploaded, go back to Q2A Admin panel, change the URL structure for that option and save it.
The successful operation of .htaccess depends on the setup of your server and site. If you are being told that neat URLs are not available in the administration center, you should review the solutions in the link below.
Read more: Why is my .htaccess file not OK?