All logo packages include a PNG with background transparency and a JPG with a white background.
Both file types are optimal for web display.
That said, I highly recommend the add-on for the source, vector & black/white files. Vectors can be scaled to very large sizes like billboards and merch without losing quality or pixelating so if you plan to use your logo in print, it is a must.
Your source files are always great to have on hand for anyone else who may provide a print or design service for you + for general safekeeping.