In my wordpress theme, there is a page name pre-registration.
if I take there any HTML form, that work but I need a congig.php file for MySQL query for this page.
Please help me to add a include(); file at that page.
How can I add custom php include() file in wordpress
If It is not a template and you are making something like plugin or your code is directly or indirectly belongs to
fucntions.phpyou can use include as you do in core PHP. If It is an template part useget_template_part()instead , if you can see some error or you have noticed nay problem, please let me know.