Postman is build for building, testing and documenting APIs. If you want to test your method You must have to create a PHP file, import the class file, create object and call the method.
You can't directly call methods in Postman.
Create file like this:
<?php import('dbConnectClass.php'); $dbConnect=new DBConnect(); // Assuming class name is DBConnect() $returnvalue=$dbConnect->methodName(); echo $returnvalue; // You can return output as JSON here. ?>