How is it possible for compound to have both ionic and covalent bonds

And ionic is when a nonmetal and a metal compound bond together and a covalent is when 2 nonmetals bond together
"K2SO4 is an example of a compound that contains both ionic and covalent bonds... the sulfate ion is held together with
covalent bonds... and the potassium ions are ionically bonded to the sulfate ions. Or let's say we have a group of elements that are covalently bonded together, but still have net positive or negative charge... like PO4, OH, SO4, NH4, NO3... and these ions are both cations and anions and can have a plethora of charges.

For example... (NH4)3PO4 can be dissociated but the ions will remain as a group. So when this dissociates... we will get three ammonium and one phosphate ion. But then, the oxygen will not dissociate from the phosphorous any more than the hydrogen will dissociate from the nitrogen."

WHen neither atom attracts or repels the shared electon it can be both.