A phospholipid structure is shown in the picture attached. It has three parts: the hydrophobic tail, the hydrophilic head and the phosphate group in the center. Thus, the function of the phosphate group is to link the hydrophobic and hydrophilic parts of a phospholipid. Specifically, the phosphate group is part of the hydrophilic head. So, it is used to connect the phospholipids to polar compounds.
