The boiling point represents the temperature at which a substance passes from a liquid state to a gaseous state, that is, so that the molecules are further apart from each other. Temperature is an indicator of the energy required, the more energy required the higher the boiling point.
Now, we are presented with our compounds, both have hydrogen and are linked with a covalent bond to an element of group VII of the periodic table, Fluorine and Chlorine. The difference between these two compounds is the type of forces around the molecules. Fluorine with hydrogen, HF molecules, forms hydrogen bonds with molecules of the same type, these hydrogen bonds are quite strong, so to separate the HF molecules from each other requires considerable energy.
In contrast, HCl molecules have weak forces on each other called Van der Wals forces, so separating these molecules requires little energy. For this reason, the boiling point of HF is much higher than the boiling point of HCl.