A notary is a lawyer (though not necessarily so in the United States) or person with legal training who is licensed by the government to perform acts in legal affairs, in particular witnessing signatures on documents. The form that the notarial profession takes varies with local legal systems.
Most common law systems have what is called in the United States a notary public, a public official who notarizes legal documents and who can also administer and take oaths and affirmations, among other tasks. In the United States, a signing agent, also known as a loan signing agent, is a notary public who specializes in notarizing mortgage and real estate documents. Although notaries public are public officials, they are not paid by the government; they may obtain income by charging fees, provide free services in connection with other employment (for example, bank employees), or provide free services for the public good. Documents are notarized to deter fraud and to ensure they are properly executed. An impartial witness (the Notary) identifies signers to screen out impostors and to make sure they have entered into agreements knowingly and willingly. Loan documents including deeds, affidavits, contracts, powers of attorney are very common documents needing notarization.
Most Roman law-based systems have the civil law notary, a legal professional working in civil law performing many more functions. The Worshipful Company of Scriveners use an old English term for a notary, and are an association of notaries practising in central London since 1373.
To "notarize" a document or event is not a term of art, and its definition varies from place to place; but it generally means the performance by a notary of a series of possible steps, which may include the following (not an exhaustive list):
Often, in the case of lawyer notaries, the certificate to be provided will not require the person appearing to sign. Examples are: certificates authenticating copies - which are mostly not within the permissible functions of U.S. notaries, and certificates as to law, such as certificates as to the capacity of a company to perform certain acts, or explaining probate law in the place.
However, in Roman Law states or provinces, notaries or "title attorneys" provide many of the same services as lawyers (negotiation and drafting of contracts, legal advice, settlement of estates, creation of a company and its status, writing of wills and power of attorney, interpretation of the law, mediation, etc...) except any involvement in disputes to be presented before a court. Notaries are specialized in all matters relating to real estate, for example, completing title exams in order to confirm the ownership of the property, the existence of any charges such as "land servitudes" or mortgages.