The distinction that costs families the most time is between a plain copy and a certified copy, and then between two grades of certified copy. A photocopy of a certificate proves nothing to an institution, so what a bank, insurer, pension administrator, brokerage or county recorder asks for is a certified copy issued by the registrar. That much is general. What varies by state is whether the registrar issues more than one kind.
California is the clearest example of a two-grade system, and it is one state's law rather than a national rule. Health and Safety Code section 103526 lets the State Registrar, a local registrar or a county recorder furnish a full certified copy where the request is accompanied by "a notarized statement sworn under penalty of perjury ... that the applicant is an authorized person," with an in-person applicant instead swearing the statement in front of the official and an electronic applicant able to satisfy it through identity proofing that "meets or exceeds the National Institute of Standards and Technology (NIST) Special Publication 800-63A Digital Identity Guidelines" and "verifies to Identity Assurance Level 2." Subdivision (b)(1) then says what happens to everybody else: if the requester "is not an authorized person or is an authorized person who is otherwise unable to satisfy the requirements of subdivision (a), the certified copy provided to the applicant shall be an informational certified copy and shall display a legend that states 'INFORMATIONAL, NOT A VALID DOCUMENT TO ESTABLISH IDENTITY.'"
The informational copy is genuine and largely useless for the jobs people need it for. It carries the same facts and is issued by the same office, so it answers a genealogical or historical question perfectly well. It is precisely the wrong document for closing an account, claiming a policy or transferring a title, because those transactions turn on establishing who is entitled to act and the legend on the face of the copy says it cannot do that. A family that orders copies without checking who is authorized can pay for a stack of documents and discover the problem only when the first institution rejects one.
Who counts as an authorized person is a relationship test. California's list for a death record covers the registrant's child, grandparent, grandchild, sibling, spouse or domestic partner, a parent or legal guardian, a party entitled by court order, an attorney representing the registrant or the registrant's estate or anyone empowered by statute or appointed by a court to act for the estate, a law enforcement or government representative on official business, and, for death records specifically, the people with the statutory right to control disposition of the remains. Two practical carve-outs sit at subdivision (e): a law enforcement or government representative acting on official business does not have to provide the notarized statement, and neither does "an agent or employee of a funeral establishment who acts within the course and scope of the agent or employee's employment" ordering certificates for those family members. That second exception is the reason the funeral director can order the first copies for a family on the day, without anyone visiting a notary.
Two features of the document itself are worth knowing before it arrives. The cause of death is certified by a medical professional and may be recorded as "pending" where an autopsy or investigation is not finished, which produces a certificate that is registered but incomplete and is later amended; institutions vary in whether they will act on the pending version. And a correction to an error in a name, date or spelling is made by the issuing registrar under that jurisdiction's own procedure, not by the institution that noticed the problem, which matters because a mismatch between the certificate and the name on an account or a deed is a common source of delay.