The usual English title of Hesiod’s poem that gives the fullest account of Pandora’s jar is Works and Days. This didactic poem combines farming advice, moral instruction, myths, and reflections on justice.
Its Pandora passage appears in a discussion of human labor and the worsening conditions of human life. After Prometheus’s theft of fire, Zeus arranges for Pandora to be created and sent to Epimetheus. The jar episode explains how troubles spread among humans while Hope remained behind.
Hesiod also mentions Pandora in the Theogony, but that account is shorter and emphasizes her role in the divine punishment associated with Prometheus. The two poems are therefore related sources, not interchangeable titles. Works and Days is the standard answer when a question asks which Hesiodic poem tells the detailed jar-opening story.