the same way you would as other Pokemon, by battling, or by exp. share
You give it a water stone and then level it up with it holding it.
Vaporeon learns Hydro Pump at level 71.
It doesn't learn Ice Beam by level up. It can learn it by TM13 in all generations though.
Level 15
Vaporeon learns Ice Beam at level 36 in Generation I. In subsequent generations, Vaporeon must be taught Ice Beam by using a TM or TR.
A Ditto and a Vaporeon will result in a baby Eevee.. The baby Eevee can evolve into 7 evolutions. Flareon with the Fire Stone Vaporeon with the Water Stone Jolteon with the thunder Stone Espeon if you level it with high Friendship during the day Umbreon if you level it up with high Friendship during the night Leafeon if you level it up in Eterna Forest near mossy Rock in the Sinnoh Region. You may have to trade it to Diamond, Pearl, or Platinum for this to Happen. Glaceon if you level it up near ice covered rock on route 217 in the Sinnoh Region. You may have to trade it to Diamond, Pearl, or Platinum for this to happen.
Vaporeon doesn't evolve. If you mean how to get it from Eevee, use the water stone.
lvl 30 or 40 something
at any level like 45,57
To get a flareon, you need a fire stone. For a vaporeon, you need a water stone. For a jolteon, you need a thunderstone. For an emporeon, have it love you, and level it up in the day time. for and umbreon, have it love you, and level it up and night.
At lv. 36
You can either train him or her or if you have gotten there put it in the day care and run around a lot. I'm doing this for my Vaporeon and it works.