What the grantor actually does, in order. Capacity comes first: an enacted Uniform Trust Code requires the settlor to have capacity to create the trust. Then intention, which is the operative act — the grantor must indicate an intention to create a trust, rather than merely to give something away or to hold something for convenience. Then the terms: who benefits, who administers, on what conditions, and what happens on death. Then the property, by one of three routes — a transfer to another person as trustee during life; a declaration that the owner holds identified property of their own as trustee, which is how someone becomes trustee of their own trust without transferring anything to anyone; or a transfer by will, which produces a testamentary trust. And then, ordinarily, nothing. The trust runs on its terms and the trustee's duties run to the beneficiaries, not to the grantor.
"Ordinarily" is doing real work in that sentence, because the exceptions are the whole of trust design. A grantor may reserve the power to amend and revoke, which is what makes a revocable living trust revocable and what makes it, for every purpose that matters to a creditor or to the tax code, still their property. A grantor may serve as their own trustee, and very commonly does. A grantor may retain an income interest, a right to occupy a residence, a power to swap assets, or a power to say who among a class of beneficiaries enjoys the property. Each of those is a decision with a price attached, and the general principle that prices them is the same one that governs the whole subject: retained control defeats separation. Property you can take back, live in, draw the income from, or redirect is treated as still yours.
The two axes a grantor's retained rights are tested against are separate, and conflating them is the classic error. The transfer-tax question is whether the property is pulled back into the grantor's gross estate at death, which turns on sections 2036, 2038, 2035 and, for a life insurance policy, 2042. The income-tax question is whether the grantor is treated as owner of the trust under sections 671 to 679, so that the trust's income lands on the grantor's own return. A trust can be inside the estate and outside the grantor trust rules, or outside the estate and inside them, and the second combination is created deliberately in some planning. Both analyses belong to other pages — the estate-inclusion tests to the irrevocable trust entry, which sets them out with the statutory sections, and the ownership rules to the grantor trust rules entry — and neither is restated here.
Who may be a grantor, and how many there can be. Any person with capacity can create a trust, and more than one person can create one together; a joint revocable trust for a married couple has two grantors, and where a trust is funded by more than one person the rules that test retained interests are applied to each contributor's share rather than to the trust as a whole. A grantor may also be a beneficiary, and in the standard revocable living trust is the lifetime beneficiary as well as the trustee. What cannot happen is that the same person is the sole trustee and the sole beneficiary, because then nobody owes a duty to anybody and there is no trust; the arrangement survives because there are successor beneficiaries behind the grantor.
The word also appears in places that are not trusts at all. Besides the deed sense, the federal deposit-insurance rules call the person who establishes an informal payable-on-death registration a grantor, and the Internal Revenue Code calls the writer of an option "the grantor of the option" at section 1234(b). None of those is the role this page describes.