Water is drunk in space by using of specialized straws and pouches with one way valves which help to prevent the water from floating away.
Astronauts also drink water by using special cups that also utilize the principles of surface tension to guide liquid to the rim for drinking.
Water is also recycled in space from various sources including condensation, sweat and urine and is purified to be cleaner than the tap water on Earth.
The reason why you can't pour water in a glass in space is because water in space does not behave the same way as it does on Earth due to the zero gravity environment in space.
Instead of pouring, the water in space would form a blob as a result of the surface tension in space and cling to the glass, or even float away as droplets.
Gravity is what pulls the water and liquids downwards on Earth and allows them to be poured.
But without the gravity, other forces such as cohesion dominate and the surface tension would cause the water to maintain it's shape as a blob.
To pour water in space you would have to provide sufficient pressure so that it doesn't immediately vaporize into tiny ice crystals as well as create a predictable environment.
In a spaceship with the right environment you could pour water in space.
Water turns to ice in a vacuum, although when in a vacuum the water first boils and then vaporizes as a result of the low pressure.
As the water in a vacuum boils, it cools down and if the vacuum is maintained and the temperature gets low enough, the remaining water can freeze.
In a vacuum, the boiling point of the water is significantly lower than at standard atmospheric pressure.
And as the pressure drops, the water will also begin to boil and turn into water vapor.
The boiling process of the water requires energy and it draws the energy needed from the remaining liquid water and causes it to cool down.
As the water then cools due to boiling, it can then reach it's freezing point.
And if the vacuum and cooling are maintained, the water will then freeze into ice.
A water phase diagram also shows that at very low pressures, the freezing point and boiling point of water also converge.
And at these low pressures, the boiling water can also cool down enough to freeze.
And even some videos demonstrate the process, which shows the water boiling and then freezing in a vacuum chamber.
And in the vacuum of space, the water would also behave in a similar way.
The water in the vacuum of space would boil initially and then then remaining water could freeze if the temperature is low enough.