Is listing that person in a will enough or are other documents necessary to ensure a trouble free transfer of home title?
Designation in a will is only one option. Taking title as joint tenants is another. A trust is a third. You should use this occasion to do some simple estate planning. Consulting a CPA and/or attorney to determine the tax and other costs is a good idea.
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Estate Planning Attorney
Using a will does not give a "trouble-free" transfer. It guarantees a probate court procedure on your death. There are other ways, like deeding the property in joint names, executing a Transfer on Death (TOD) deed, executing a life estate deed, or creating a trust. Each solution has its specific advantages and disadvantages. The most flexible is creation of a trust. The least flexible (arguably) are joint tenancy or life estate, since they cannot be changed without the other party agreeing. But those ways have their advantages also, including protection from Medicaid liens.
I am not your lawyer. Any advice given through the Avvo site is for hypothetical purposes only, and does not create an attorney-client relationship. The advice is without warranty and you should not rely on this advice without consulting a Wisconsin attorney directly who knows the particulars of your case.