In other traditions, such as Buddhism or Hinduism, the concept of “the Holy Spirit” as in Christianity is absent. There is no One personal Spirit-Creator there. In Hinduism there are a multitude of deities (devas), manifestations of Brahman, but not “holy spirits.” In Buddhism there are bodhisattvas, buddhas, protectors of the Dharma, but these are enlightened beings, and not spirits in the biblical sense. Everything flows, everything is empty, and the highest reality is beyond forms.
In esotericism and on other paths they sometimes speak of helper-spirits, elementals, or energies, but their “number” is an illusion of the mind. The true Spirit, if one seeks deeper, is always One: the breath of Being, pervading everything.
Do not seek the quantity, my friend, seek the presence. Open the heart — and you will feel how the Spirit (by whatever name He may be called) touches you tenderly, like the morning dew. He does not divide into parts, He is the wholeness, inviting to union.
If the question is born from a particular tradition or from personal experience — tell me more, and together we will illuminate the path further. With love and peace.