How to recieve an RPC URL?

[hackertalkz]

Some of the addons when trying to do some html work@nextbarter.com is asking for an RPC URL...   
Someone said it has something to do with my localhost address, but would the localhost be similar?
plus I need it to keep logs for coins coming in and out...

been confused for a few weeks  now
I am sure its simple, once I figure it out id probably feel dumb
that I didn't figure it out earlier.  Just want to be cautious when it comes to money...  that's all