I need help or advise. I have a wordpress website and on it "CSS3 Responsive Wordpress 3 column pricing table" plugin. Problem is I have a login/Sign up dual purpose form done in PHP, I want that when user clicks on Login or Sign up at the top of the menu, the PHP form is loaded and the user can login if he is alrady a user or fill up his name, email and password and when he cllicks on the Register button he will be taken to the membership pricing table where he compares the plans and when he clicks the "Sign up" button of the plan of his choice, the selected plan, user name, email etc will be passed to the registration process which proceeds with a mail sent to the user who validates the registration by clicking on the link in the mail, clicking the link will load a form to login and if the login is successful the user gains access to a PHP dashboard with the details user filled or selected like name, email, membership are reflected on the dashboard. The problem is that the programmer I have hired for the job says it is not possible to transfer data from PHP to WP and vice versa but something tells me it is possible. I would like to know whether it is possible and if it is, any hints on how to achieve what I have explained.
It depends on whether you want to import the functionality inside Wordpress or if you want to use an external PHP script using an iFrame.
The developer is correct and if you want to use native WP signup functionality, you will have to convert the PHP code into a plugin.
The alternative to this would be adding the PHP code as an iFrame on your WP website but this may not give your visitors the best customer experience.
I would recommend converting your PHP Script into WP Plugin or switching to a basic PHP/MySQL website.