hello friend i am developing a web site in which online payment is there so it is school website so online fee payment is there so i dont undestand from where i start so pls give me source code and the process also pls help me out.

You can use paypal IPN for that.
Website owner must have business account in paypal.
Once account is generated he can create API credintials i.e. API_UserName, API_Password, API_Signature which will be used in php coding.
Here is a sample code link : https://cms.paypal.com/cms_content/US/en_US/files/developer/nvp_DoDirectPayment_php.txt

Now in your website you have to give credit card payment form. and as in above code it will pay directly to business account.

Be a part of the DaniWeb community

We're a friendly, industry-focused community of developers, IT pros, digital marketers, and technology enthusiasts meeting, networking, learning, and sharing knowledge.