Hyperspace is accessible through wormholes. It is generally used as a shortcut to allow interstellar/intergalactic travel. Hyperspace is quite dangerous, so there are established routes to frequently-accessed points. Travelling off these routes certainly won't result in certain death, but is quite dangerous as most of Hyperspace is not protected from vacuum fluctuations that have a tendency to impart energy to ships, sometimes enough energy to obliterate them.
The FTL Drives on most ships cannot provide enough energy to travel between galaxies; however, system hyperspace-access gates are capable of intergalactic and in some cases inter-galactic-cluster travel.