Acrylic paint is water-soluble when wet and yet because it is a plastic polymer, dries into a flexible, water-resistant and durable surface to which subsequent layers of paint could add without disturbing the underlying layers.
Since acrylic paint dries quickly, you can work in multiple successive layers without muddying the colours. A spray bottle of water is required to slow down the drying time a bit, both on the palette and the painting.
You can almost find it in tubes, plastic squeeze bottles, in jars or a small ink-bottles. It also can come in different thickness, those in tubes being the most vicious that similar to the oil paint. Whatever form that you use, it is essential to ensure that the paint is sealed completely to keep the paint from drying out fast, particularly for large tubes and jars.
Although acrylic paints are well-known for their bright colours, many of the colours are the same as oil and can be applied in a way that is indistinguishable from the oil paints. Moreover, some mediums can thicken the paint and delay the slowing time so that the paint could manipulate the same way as the oil paint.