Broadly, the act of proving that something (e.g. a document) is true or genuine.
FDFA website, [Authentication of Civil Documents](https://www.eda.admin.ch/dam/countries/countries-content/philippines/en/Authentication_Civil_Doc_EN.pdf) (6.3.2019).
Notaries are primarily concerned with the authentication of signatures, authority and capacity relating to documents for use abroad.
‘Authentication’ and ‘authenticate’ are the terms to use when referring generally to the process of authenticating documents, signatures, identities, transactions, corporate existence, etc.
Based on Black’s Law Dictionary, West Group, 1999, p. 127 (6.3.2019).