A last will and testament is only legally valid once it has been signed by two witnesses as well as the testator. The only requirements for the witnesses is for them to be “generally competent.”
If all three signatures are properly notarized, a will is considered to be “self-proving.” If the will qualifies as “self-proving” then a probate court will not require the calling of witnesses to verify the authenticity of the will in the event that the estate requires probate proceedings. When executing a self-proving will, the notary may also serve as one of the witnesses.
Historically, an “interested witness” would not count as a valid witness if they stood to inherit under the will. However, Utah law no longer prohibits that and an interested witness no longer invalidates the will. Utah code 75-2-505(2) states that “the signing of a will by an interested witness does not invalidate the will or any provision of it.”