This page shows you how the logo looks against different backgrounds.

The “.png” format is for use on the web and is the only format shown on this page. 

The .jpg format is not transparent meaning the logo will be inside a white square.  It is not useful.

There are other formats intended for professional printers.  These are the .ai, .eps and .svg formats. You will not be able to open them without commercial software.  They can be expanded up to billboard size without blurring.  When dealing with a professional printer, provide them with whichever one of these formats they prefer.  The professional formats will look exactly like the logos on this page.