Hydrogen bonds are forces of attraction that form between hydrogen atoms and a highly electronegative atom such as fluorine, oxygen, and nitrogen. In the case of water, the hydrogen bond forms an attractive force between a hydrogen atom and the lone pair of electrons of other oxygen atoms in the water molecule.
What happens is that a partially positive atom like hydrogen in one molecule is attracted to the partially negative atom of another molecule, causing a hydrogen bond to be formed. The hydrogen bond in water molecules is responsible for the many unusual properties of water. For instance, there are so many molecules that are similar to water in terms of mass, but they are gases at room temperature.
Water molecules are able to maintain their liquid state because of the attractive force of hydrogen bonds that exists between them. It is important to note that hydrogen bonds are also stronger forces compared to other forces of attraction, like the ordinary dipole-dipole force.