When energy converted in to mass the particle which formed initially possess charge. What that particle is, not known exactly it may be God particle or something else yet to be discovered. For charge I can say that it is the energy stored in the matter particle which is electrical in nature and have the ability to create a field of influence around it in which another charged body will experience force of repulsion or attraction. These elementary particles keeps on adding till they acquire stability and turned out in to a proton or an electron. A minimum fixed quanta of energy get stored in these particles.
Now Please reflect on and share your views
As well Please reflect on the questions below
How a Proton became positively charged or an electron became negatively charged ?
What actually this positive and negative mean ?
Reflects in comments