You asked about Europa, a Moon of Jupiter, not Europe.
I don?t think many people know. I?ll use Jupiter to approximate. The length of time required is dependent upon your purpose of travel.
It took the New Horizons spacecraft 13 months from its launch in January 2006 to reach Jupiter in February 2007.
Voyager 1 took 18 months from its launch (September 1977) to its arrival at Jupiter (March 1979).
The Galileo spacecraft took 6 years from its launch (October 1989) to its arrival (December 1995).
A difference was that Voyager 1 and New Horizons were on their way elsewhere, Galileo was aiming to go into orbit around Jupiter. The time for a manned mission could depend on rocket capabilities. I think a Hohmann transfer orbit would have a period of 5 years, thus a one-way travel time of 2.5 years but I think this would require a delta-v. If you don't have a delta-v then you have to do some gravity-assist manoeuvres with Earth and/or Venus and that will increase the time. Such a spacecraft would have to be constructed in Earth orbit because of the much greater mass of supporting hardware needed for the humans on board and the greater mass of fuel needed to accelerate that mass