Fair copy petitions (otherwise known as 'King's Bills'), prepared by the Clerks of the Signet, for grants, pardons, commissions, etc., which were submitted via the Secretaries of State to the King for signature with the sign manual, which transformed them into warrants to the Signet for action to be taken.
The King's Bills do not represent all petitions to the King, but those which had gone through some kind of official check first, apparently administered by the Secretaries of State. Most have a precis (in English) for the King. If the petition was an official one, it bears the signature of the drafter (usually one of the law officers) and gives the authority on which it was drafted.
The series was previously known as State Papers Domestic Warrants.