This series contains files of general warrants, warrants for certificates of homage, and fiats for protections, which were prepared by the Clerks of the Signet and forwarded to the Office of the Keeper of the Privy Seal as his authority for making out a writ of privy seal. The collection is very incomplete as these warrants were generally retained by the several Lords Privy Seal.

These signet warrants were almost all written in response to petitions. All grants of annuities, lands, offices, wardships, and pardons, and many of justice, were secured by petitioning the king. The most important warrants, authorising grants of land, annuities, or bishops' temporalities, were sent to the Keeper of the Privy Seal because the Chancellor needed a privy seal warrant to authorise him to issue such grants under the great seal.

Other signet letters sent to the Keeper of the Privy Seal were for royal gifts of minor importance, and for minor grants (e.g. letters of passage, permitting the bearer to leave England by a certain port). In such cases, the privy seal warrant acted as an immediate authority to the relevant royal officials, and was not sent on to the chancellor for issue under the great seal.