The 12th house is a closed house, the house of solitude, immersion in oneself, in one's inner world. And Jupiter is the planet of expansion, high ambitions and distant goals. And here the person hides a lot - their goals, ambitions, needs - a very specific position. They are more focused on finding themselves, on inner growth and development, on spiritual aspirations, rather than on social growth.
This does not mean that the person does not work and sits in their closed little world. Not at all. We all live in society and revolve in it. They can perfectly well realize themselves in some closed institutions and be successful in this circle, but not for public display. Either the person realizes themselves in the professions of the 12th house - psychologists, researchers, forensic scientists, doctors, employees of secret services, astronomers, space explorers, occultists, tarot readers, astrologers, numerologists, yoga teachers and many, many others. Or the person is realized abroad, success is somewhere there, far from their homeland.
That is, the person works in society and can be successful, but the need to shine and seek success for the masses, as such, is not really there. They may be known in their field, in their circle - and this is more than enough for them. Here the person is rather directed inward, to their aspirations, to their needs, than to social achievements.
And it often happens that they are put under pressure from the outside, insisting that they must achieve external success, climb the career ladder. Parents press: family, husband, wife, and the person tries, tries, and in the end retreats even more into themselves. Until they finally understand that this is not what they need, and not their goal.
About Jupiter in the 12th house, one can often hear the expression "Angel on the Shoulder". What is that? The 12th house is still a complex house, the house of limitations, hospitals, prisons. And if a person finds themselves in a difficult situation, it is believed that Angels somehow help them, illuminate the path, guide them in the right direction. As if the invisible world supports the person, helping them in these difficult situations.