Ana is a Support character who uses her rifle and other abilities to simultaneously heal her teammates and hurt her foes--and she just so happens to be Pharah's mother, too. You can try her out for yourself through the Public Test Realm right now.
As Ana you'll use her Biotic rifle most of the time. She is shooting darts and heals allies, but it also deals damage to enemies with her Sleeping dart (knocks them up).
Ana can utilize her Biotic Grenade, which heals teammates and damages opponents standing within its small area of effect.
Ana's ultimate is Nano Boost which gives her teammate more damage, faster movement speed and a higher damage resistance.
Ana's Legendary and Epic skins offer some new looks for the healing sniper. She has one skin that makes her look like her younger self, and another that looks like it's been pulled straight from Future.
We all thought her name will be Sombra, but maybe we will expect Sombra in the future.
If you want to try Overwatch you can buy it on their official site - OVERWATCH