Dear student,
Charge is conserved means you cannot create or destroy charge. All you can do is transfer it from one body to another or such sort of things. You cannot make a charge in anyways, all the charge you get is what you will have. Meanwhile, charge is quantised means you can remove or add or transfer charge only in quanta( in packet like photons or specific quantity). This is the charge of an electron e=1.6×10^-19 c. You cannot remove a charge e/2 or e/4 from no where, or add it to anywhere. You can do it only in quanta of e. Which means an electron is the smallest charge you can transfer. You will know these stuff more in your upcoming studies. Hope it helped.
thank you.