Water is a polar molecule because it has a bent shape, meaning that the electronegative oxygen atom and electropositive hydrogen atoms are on different sides of the molecule.
The polar property means that other polar compounds e.g. salts are attracted to the partial positive and partial negative charges on the hydrogen and oxygen atoms in water.
e.g. table salt (sodium chloride) dissolves well in water because the positive sodium ions are attracted to the negative oxygen atoms, and the negative chloride ions are attracted to the positive hydrogen atoms.
Other polar molecules are also attracted to the water molecule.
e.g. in etanol the positive hydrogen atom is attracted to the negative oxygen atom in water. This forms a hydrogen bond - a strong intermolecular interaction.