With the exceptions of Louisiana, Puerto Rico, Quebec, whose private law is based on civil law, and British Columbia, whose notarial tradition stems from scrivener notary practice, a notary public in the rest of the United States and most of Canada has powers that are far more limited than those of civil-law or other common-law notaries, both of whom are qualified lawyers admitted to the bar: such notaries may be referred to as notaries-at-law or lawyer notaries. Therefore, at common law, notarial service is distinct from the practice of law, and giving legal advice and preparing legal instruments is forbidden to lay notaries.

Notaries are appointed by a government authority, such as a court or lieutenant governor, or by a regulating body often known as a Society or Faculty of Notaries Public. For a notary-at-law, an appointment is usually for life, but lay notaries are commissioned for a briefer term with the possibility of renewal. In most common-law countries, appointments and their number for a given notarial district are highly regulated. However, since the majority of American notaries are lay persons who provide officially required services, commission numbers are not regulated in America, which is part of the reason why there are far more notaries in the United States than in other countries (4.5 million vs. approx. 740 in England and Wales). Furthermore, all U.S. and some Canadian notarial functions are applied to domestic affairs and documents, and fully systematized attestations of signatures and acknowledgment of deeds are a universal requirement for document authentication. By contrast, outside North American common-law jurisdictions, notarial practice is restricted to international legal matters or where a foreign jurisdiction is involved, and almost all notaries are also qualified lawyers.

For the purposes of authentication, most countries require commercial or personal documents which originate from or are signed in another country to be notarized before they can be used or officially recorded or before they can have any legal effect. To these documents a notary affixes a notarial certificate which attests to the execution of the document, usually by the person who appears before the notary, known as an appearer or constituent (U.S.). In places where notaries-at-law are the norm, a notary may also draft legal instruments known as notarial acts which have probative value and executory force as would any lawyer's writing. Originals or duplicate originals are then filed and stored in the notary's archives, or protocol.

Notaries are generally required to undergo special training in the performance of their duties. Some must also first serve as an apprentice before being commissioned or licensed to practice their profession. In many countries, even licensed lawyers, e.g., barristers or solicitors, must follow a prescribed specialized course of study and be mentored for two years before being allowed to practice as a notary (e.g., British Columbia, England). However, notaries public in the U.S., of which the vast majority are lay people, require only a brief training seminar and are expressly forbidden to engage in any activities that could be construed as the practice of law unless they are also qualified attorneys. Yet, despite these apparent differences, notarial practice is universally considered to be distinct and separate from that of attorney (solicitor/barrister).

In bijuridical jurisdictions, such as South Africa or Louisiana, the Office of notary public is a legal profession with educational requirements similar to those for attorneys. Many even have institutes of higher learning that offer degrees in notarial law. Therefore, despite their name, "notaries public" in these jurisdictions are in fact civil-law notaries.

For a more detailed account, see Civil-law Notary.

Notaries Public (also called "notaries", "notarial officers", or "public notaries") hold an office which can trace its origins back to ancient Rome, when they were called scribae ("scribe"), tabellius ("writer"), or notarius ("notary"). Their work would later be transcribed correctly in its entirety by a calligraphus. They are easily the oldest continuing branch of the legal profession worldwide.[citation needed]

The history of Notaries is set out in detail in Chapter 1 of Brooke's Notary (12th edition):

The duties and functions of notaries public are described in Brooke's Notary on page 19 in these terms:

A notary, in almost all common law jurisdictions other than most of North America, is a practitioner trained in the drafting and execution of legal documents.[citation needed] Notaries traditionally recorded matters of judicial importance as well as private transactions or events where an officially authenticated record or a document drawn up with professional skill or knowledge was required. The functions of notaries specifically include the preparation of certain types of documents (including international contracts, deeds, wills, and powers of attorney) and certification of their due execution, administering of oaths, witnessing affidavits and statutory declarations, certification of copy documents, noting and protesting of bills of exchange, and the preparation of ships' protests.