Charge annihilation, simply put, is when positively and negatively charged particles meet, disappear together, and convert into energy.

The most common example is electron-positron annihilation.
An electron is a tiny negatively charged particle and a component of atoms.
A positron has the same mass as an electron but carries a positive charge — it is the electron’s antiparticle.
When these two particles come into contact, they do not bounce off each other like small balls.
Instead, they vanish instantly.
The positive and negative charges they carried disappear as well, turning into photons — pure light energy.

A critical rule applies here: charge cannot vanish on its own.
Positive and negative charges are equal in amount, so their total charge is zero.
After annihilation, the total charge remains zero, fully obeying the law of conservation of charge.
Charge never disappears unilaterally for no reason.

How can charge arise out of nothing?

The reverse of annihilation is possible: charge can emerge from energy with no initial charge.
This process is called pair production.

Light is a form of energy.
When high-energy light (such as gamma rays) passes near an atomic nucleus,
under the influence of the nuclear force,
it suddenly transforms into an electron and a positron.

Light, originally carrying no charge at all,
becomes a pair of particles with equal and opposite charges.
New charge is thus created.

This process also obeys the law of conservation of charge:
the initial light has zero charge,
and the produced positron and electron — one positive, one negative —
still sum to zero net charge.
No extra charge is created out of nothing.