A class is a set of abilities that a character can take on. Some role-playing games give playable characters fixed classes that can't be changed and are specific to the character, while others allow class changes, for example in Final Fantasy III and V with its job system where characters can switch their current class, or allow characters to gain levels in multiple classes, such as Neverwinter Nights.
Most games include basic classes such as a warrior who is generally best at physical weapon based attacks, the magician who specializes in damaging magic spells, and the healer who is able to keep other party members alive in the battle by restoring their HP and canceling detrimental status conditions using spells.
In the database of an RPG Maker game in the releases where class options are built in, it is possible to select the default class of each actor in the game. Event commands may also be available to switch a character to a completely different class, though this is not required to be used. These classes may also be named by the developer. Generally, for games where class changing is an option, classes are named to reflect their abilities in combat, such as a thief or rogue revolving around stealing items from enemies, or a cleric or white mage specializing in healing magic. Games where classes are fixed are more likely to instead have class names based on their title or species, for example a wolf character may have her class named "Alpha Wolf," a cleric of "Soma" might have a class name of "Soma's Will," while the main hero could simply have a class name of "Hero."
In RPG Maker, there are no default mechanics allowing for mixing and matching classes (aka Multiclassing), and class switching is binary, with all characters having all their current levels in one specific class. Custom plugins or scripts are required for characters to be in multiple classes at once without making combination classes to simulate the effect.