Definition: According to the additive feature of electric charges, if there are n charges represented within, the total charge available seems to be the algebraic addition of the particular charges.
Due to the obvious additive nature of the charge, the total electric charge of such a structure would be equivalent to the algebraic summation of the electric charges present throughout the structure or system.
The rule of superimposition of electric charge explains the additive nature of the charge.
Therefore, additive nature of charge is one of the features of electric charge is its cumulative nature.