It has custody of the Great Seal of the Realm, and has certain administrative functions in connection with the courts and the judicial process, as well as functions relating to the electoral process for House of Commons elections, to the keeping of the Roll of the Peerage, and to the preparation of royal documents such as warrants required to pass under the royal sign-manual, fiats, letters patent, etc.

[8][9] The Crown Office is involved in the royal assent process, both when this happens in person by the Lords Commissioners and by notification to both Houses of Parliament.

When royal assent occurs at the Prorogation of Parliament, the Clerk of the Crown reads out the short titles of Acts due to receive royal assent, after which the Clerk of the Parliaments notifies both Houses of royal assent to every Act with the endorsement "Le Roy le veult" if the monarch is male, or "La Reyne le veult", if the monarch is female.

The Clerk of the Crown in Chancery, whose office has, since 1885, been held in addition to the position of Permanent Secretary at the Ministry of Justice,[22] is the titular head of the Crown Office, though this distinction is regularly used by the Deputy Clerk; they are appointed by the Monarch under the royal sign-manual.

[23] The Clerk of the Crown also holds the responsibilities of the old office of Secretary of Presentations,[24] which was part of the Lord Chancellor's Department and gave recommendations on the appointment of senior members of the Church of England and other ecclesiastical patronage work.