i need 230v to 5V 2A power supply board circuit for PCB design
Use an existing power supply and incorporate it into your design. It will be the cheapest option initially. When you are ready to produce the product in 1K quantities then work with a company that has the required experience in that area.
My assumption is that you are interested in a switching power supply and not a 50-60Hz line frequency transformer approach.
If you really want to learn how to design power supplies then this is not the place to do it. And if you think that you will be able to make a power supply cheaper than to buy one then you have no idea what you are doing.
Since you may not take the good advice offered I will give you what you asked for.
10W Power Supply Reference Design http://www.ti.com/tool/pmp9517 (http://www.ti.com/tool/pmp9517)