You don't say what info you want, but it's likely your present mortgage company has the ability to do a HARP refinance and can answer your questions.
You can also do some reading as well as find participating lenders at: https://www.harp.gov/
While this website seems legit, don't complete any forms online just in case. I don't see any, so again "just in case." Get the info and move forward from there.
Best of luck!