USPS & My Website

How do I implement USPS into m site? I signed up for an account on there website but don't know where to go from there.
I am able to sign in but other than that I don't know what to do.

Thanks.

They have an API which you can use to perform various tasks. You need to download their documentation from their website and run various tests to verify you are using the API correctly. Then you need to seek permission to go live. You also may need to seek permission to use some parts of their API even after successfully testing.

Thanks.

USPS provides an interface for programmers from where you can download guide and sample code to integrate.

The script is very simple and you will just have pass values into a function to get the online rates.