Only 3 of the 5 valence electrons of the phosphorus are used for bonding with chlorine, so the other two are unshared.
Polar molecules have polar covalent bonds or ionic bonds.
The atoms having higher electronegativity value attract the electrons pair from the bonding partners.
A carbon atom has a lower electronegative value than a fluorine atom.
Two of the electrons are shared with two chlorine atoms to form two covalent bonds.
When the vector number of these dipoles of the XeF4 molecule is computed, the resultant dipole moment is a net-zero Debye.