(a) Quantization of electric charge. It is now a well known fact that all charges occurring in nature are positive or negative integral multiples of a basic unit of electric charge which we take as the magnitude of the charge on an electron. We use symbol e for the amount of charge on an electron. Hence charge on an electron is $-e$ and that on a proton happens to be $+e$, while charge on a neutron is zero. Any charged body will have $\pm$ ne charge, where $\mathrm{n}$ is an integer. This fact is called the quantization of electric charge.
(b) At the macroscopic level one deals with charges that are enormous compared to the magnitude of charge e. Since e $=1.6 \times 10^{-19} \mathrm{C}$, a charge of magnitude, say, $1 \mu \mathrm{C}$ contains something like $10^{13}$ times the electronic charge. At this scale, the fact that charge can increase or decrease only in units of $e$ is not very different from saying that charge can take continuous values. Thus, at the macroscopic level, the quantisation of charge has no practical consequence and can be ignored.