'If a body has a potential (or Voltge) it must posses an excess charge to give it that voltage.'
'his charge can either be positive or negative , it doesn't matter which. However, the type of charge does decide thedirction of the electric field.'
It the first sentence: It must posses an excess charge to give it that voltage. Does the Excess charge give the body the potential/ voltage or does the potential /voltage give the body the excess charge?
The excess charge gives the body an electrical potential. That potential is called voltage.