A more thorough explanation:

The Stationery Office was a government office in England that was established in 1786. Its purpose was to provide government offices, including Parliament, with stationery and books. It was also responsible for printing and publishing government papers.

Another name for the Stationery Office was Her Majesty's Stationery Office.

For example, if a government office needed pens, paper, or other supplies, they would order them from the Stationery Office. The Stationery Office would also print and distribute important government documents, such as laws and reports.

The Stationery Office played an important role in ensuring that government offices had the necessary supplies and materials to carry out their work efficiently.