In Modern English, it is a singular, neuter, third-person pronoun.
In Modern English, it has only three shapes representing five word forms:
it: the nominative (subjective) and accusative (objective) forms. (The accusative case is also called the "oblique".)
its: the dependent and independent genitive (possessive) forms
itself: the reflexive form
Historically, though, the morphology is more complex.
Old English had a single third-person pronoun – from the Proto-Germanic demonstrative base *khi-, from PIE *ko- "this" – which had a plural and three genders in the singular. The modern pronoun it developed out of the neuter, singular. The older pronoun had the following forms:
This neuter pronoun, like the masculine and feminine ones, was used for both people and objects (inanimate or abstract). Common nouns in Anglo-saxon had grammatical genders, which were not necessarily the same as the gender of the person(s) referred to (though they tended to accord with the endings of the words). For instance, Old-english (the ancestor of "child", pronounced "chilled") is neuter, as are both and , literally "male-child" and "female-child" (grammatical gender survives here; some 21st-century English speakers still use "it" with "child", see below).
The word , (which meant "female", ancestor of "wife" as in "fishwife"), is also neuter. ("Man") was grammatically male, but meant "a person", and could, like , be qualified with a gender. (variant , ancestor of "woman") meant "female person" and was grammatically masculine, like its last element, , and like (variant , "male person"). Archbishop Ælfric's Latin vocabulary gives three Anglo-saxon words for an intersex person, (dialectical "skratt", grammatically masculine), (grammatically feminine, like its last element, ), and (grammatically masculine).
Similarly, because is feminine, so are (inhabitants of a region), (inhabitants of heaven), and (inhabitants of hell). is neuter, feminine, and both mean "the Angles, the English people". Nouns for inanimate objects and abstract concepts also had (grammatical) genders.