A more thorough explanation:

Her Majesty's Stationery Office, also known as the Stationery Office, was a government office established in 1786 to provide stationery, books, and printing services for government offices, including Parliament. It was a department of the treasury and responsible for printing and publishing government papers.

For example, if a government office needed paper, pens, or other stationery supplies, they would order them from the Stationery Office. Additionally, if the government needed to print or publish a document, such as a report or a law, they would use the services of the Stationery Office.

The Stationery Office played an important role in ensuring that government offices had the necessary supplies and resources to carry out their work efficiently. It also helped to ensure that important government documents were printed and published accurately and in a timely manner.