Wicca as a religion is usually considered polytheistic, which means the worship of many gods. In practice it also means many ways of looking at the whole question of deity and great tolerance for each others various answers or lack of same. (We do not, however, include in our numbers those who practice Satanism, considering that to be a reverse form of Christianity.)
There are Wiccans (and other Pagans) who are agnostics, or even atheists. Some are animists, believing that everything is alive, and some are pantheists, believing that God is Everything and Everything is God. Some are classical polytheists, and some are monotheists who believe that divinity is ultimately one, though manifesting in different aspects. Most Pagans believe in immanence, that is, the divine manifest in the world, including in us. Others believe in both immanence and transcendence (the divine above creation, on some spiritual plane). Some people believe in the literal existence of their deities. Others talk in terms of archetype or metaphor or symbol or the personification of natural forces.
And some people never trouble their minds about the whole subject. To quote a perceptive observer, Worship of divinity . . . is not the primary experience of Paganism. Celebration of Nature is more central, especially as it is experienced as Earth and body. (Graham Harvey in Contemporary Paganism, N.Y. University Press, 1997; ISBN 0-8147-3549-5.) Margot Adlers Drawing Down the Moon (Beacon Press, 1987; ISBN 0-8070-3253-0) also surveys Wiccan and neo-Pagan beliefs.
But there are Wiccans (and other Pagans) who are deeply involved with specific deities, or with particular pantheons such as the Greek, Celtic or Norse. Others are devoted to the God and the Goddess, sometimes unnamed. Some feminists are interested only in the Goddess. And there are people who blithely make up their own deities, in the playful, irreverent spirit of the movement.
But most Pagans, and certainly all Wiccans, when they speak of deity do so in terms of the feminine as well as the masculine not just God the Father but also Goddess the Mother. In fact, for Wiccans the Goddess is predominant, however much we try for "balance" and "polarity". It is natural to think of the Earth, out of whose substance we are formed and whose body nourishes us, as the Great Mother. The idea is out there in the wider world as Gaia, the earth as a living entity, the name coming from a Greek Goddess. (Scientists merely talk of Gaia as a self-regulating system, but lay-people tend to think "living".) But of course, the Earth does not produce life all by herself, but in partnership with the "fertilizing" energy of the Sun, the primeval Father. The combination of "masculine energy" and "maternal" matter comes alive in animals and plants and in us, the children of the gods.