What is the difference between charge and current?

An electric charge can be either negative or positive. The smallest quantity of negative charge is the amount represented by one electron, and this is exactly equal to the amount of positive charge represented by one proton. In practice, charge is measured in coulombs (C).
Normally, atoms have identical numbers of protons and electrons, so atoms are normally neutral. Atoms that are charged are called 'ions'. A 'positive ion' has an overall positive charge, which means it has more protons than electrons. A 'negative ion' has an overall negative charge, which means it has more electrons than protons.

'Free electons' are negatively-charged sub-atomic particles that have become detached from an atom. Most metals have an abundance of free electrons, and it is a drift of these free electrons that constitute an electric current. In electrolytes (conducting fluids) a current is usually a movement of positive or negative ions.

In both cases, an electric current is a drift of electrical charge. An electric current is measured in amperes (A).

The ampere is an SI base unit, and defined in terms of the force between parallel, current-carrying conductors, due to their magnetic fields. A coulomb is an SI derived unit, defined in terms of current and time, as an ampere second.