Information provided to the voter that describes the procedure for marking the ballot. This information may appear directly on the paper or electronic ballot or may be provided separately.
Source: Election Terminology Glossary - Draft, National Institute of Standards and Technology (NIST), https://pages.nist.gov/ElectionGlossary/;
Information provided to the voter during the voting session that describes the procedure for executing a ballot. Such material may (but need not) appear directly on the ballot.
Source: Glossary of terms database, U.S. Election Assistance Commission, https://www.eac.gov/glossary/