Now, what does it mean to have 7th house lord sitting in 12th house?

It means the planet which rules/controls/owns the 7th house of your horoscope is sitting in the 12th house of horoscope.

Now, what is the impact of having 7th house lord sitting in 12th house?

Its generic interpretation is that your spouse is somehow getting linked to Foreign Lands, Spirituality and Imagination. Either your spouse is coming from a Foreign Land or you are going to Foreign Land with your spouse. As 7th lord is going into 12th house, later option becomes a higher possibility. It also shows that your spouse will be the one who may initiate you in spiritual practices. It also shows that your spouse may be working in MNCs, Hospitals or Jails. If there are malefic planets impacting 7th lord in 12th house then it may shows that you have to incur losses due to spouse but it may be in some particular dashas, not whole life. It also shows that Foreign Lands become a kind of obstacle in marriage as 12th house is 6th from 7th house. So, it indicates obstacles in marriage. For such things, we need to analyse whole chart.

Now, results may be different due to aspect, conjunctions of other planets or the planet being Retrograde or Combust. Moreover, now we also need to check the strength of 12th house lord as 7th house lord is going in 12th house. So again, Overall Chart Reading is important.

So, let's see how different planets will behave differently as 7th house Lord in 12th house.

Sun - Suppose it is a Aquarius Ascendant chart and Sun rules the 7th house with Leo sign and sits in the 12th house in Capricorn. This shows that your spouse may be working in an authoritative position in Foreign Lands or even with Govt in Foreign Lands. It also shows that your spouse has a low self esteem and there is always an special effort made to overcome this inferiority complex. In order to overcome this inferiority complex, there are constant ego battles between native and spouse which leads to disputes in relations. Again, any other yoga or dasha can change the scenario totally.

Moon - So it is Capricorn Ascendant Chart and Moon rules the 7th house with Cancer sign and sits in 12th house in Sagittarius. It shows that your spouse is a very religious and spiritual minded person. Spouse is surely going to benefit from Foreign Lands. Native's mom herself would have great benefits from Foreign Lands. This also shows that spouse helps the native to develop his spirituality and imagination. Native/Spouse/both can be very creative and imaginative. Spouse may be working in field of Religion, Philosophy and Higher Learning. Here, you may get married to a Priest or Pastor too.

Mars - Mars can be 7th house ruler through its two signs. So, let's take both one after the other.

Libra Ascendant - So if it is Libra Ascendant, Mars rules 7th & 2nd house and sits in 12th house in Virgo sign. This shows a spouse who is most probably in Health Care field. Virgo is Healing, Mars isa Doctor/Surgeon and 12th house is hospitals. Native's family shifts to Foreign Lands. This can also show someone working in Law Enforcement Agencies like Police or Jail Staff. This shows a person who is highly perfectionist. Arguments take place in relationships only when that perfectionist approach is disturbed or not satisfied. Spouse may have a very direct and specific speech.

Taurus Ascendant - Now if it is Taurus Ascendant, Mars rules 7th & 12th house and sits in 12th house in Aries sign. As Mars is in own sign here, this is a very strong position of Mars. Here, Spouse becomes like protector of relationship as Mars aspects back at 7th house, hence protects its own house. Here Spouse is an action oriented and motivated person. They get good wealth from Foreign Lands. At right time, they settle in Foreign Lands. Profession of Spouse would be similar like in Health Care and Law Enforcement. Additionally, this can make a person an Athlete who travels Foreign Lands to compete with others. Actually, Athlete is a possibility with earlier position too as Virgo is also a sign of Competition.

Mercury - Mercury also can be 7th house ruler through its two signs. So, let's take both one after the other.

Sagittarius Ascendant - If it is Sagittarius Ascendant, Mercury rules 7th & 10th houses and sits in 12th house in Scorpio. Here is a spouse who is a Mystic. Mercury is Karaka of Astrology, Scorpio is sign of Occult and 12th house is your hidden talents. So, spouse here is very much into occult and mysticism and would love to communicate about it. They would be author of Occult related books. Actually, the relation will prosper more and more as they communicate about Occult and like stuff. A very imaginative and skilled spouse.

Pisces Ascendant - If it is Pisces Ascendant, then Mercury rules 4th and 7th house and sits in 12th house in Aquarius. In the most generic sense, spouse here is working in Foreign Lands in Large Organization or MNCs in a job where communication and analysis of details is a great part of work. It can make them work in Analytics and Accounts/Audit related fields. They are very clever with communications, at times cunning. They are also very perfectionist about what they say or write. They can be working with some group of people involved in Scientific and Technical innovation, for the betterment of Society.

Venus - Venus also can be 7th house ruler through its two signs. So, let's take both one after the other.

Scorpio Ascendant - If it is Scorpio Ascendant, Venus rules 7th & 12th house and sits in 12th house in Libra sign. As Venus is in its own sign, this is a real good position. As Venus also represents Wealth, it shows that lots of wealth from Foreign Sources. It shows that after marriage, native moves to foreign lands with spouse and gains there. It also shows your spouse is very creative and that creativity can also bring an extra income. Overall, a very good position.

Aries Ascendant - If it is an Aries Ascendant, Venus rules 2nd & 7th house and sits in 12th house in Pisces, where it is exalted. This one is best as Venus is getting exalted here. Results of earlier Venus position is increased manifold here. Spouse is Spiritual and adds Spirituality and Devotion in native's life. Wealth increases tremendously in Foreign Lands. Spouse would be fond of visiting Spiritual Places. A relation based on Spiritual and Devotional Values.

Jupiter - Jupiter also can be 7th house ruler through its two signs. So, let's take both one after the other.

Gemini Ascendant - If it is Gemini Ascendant, Jupiter rules 7th & 10th house and sits in 12th house in Taurus Sign. This shows a spouse who is very learned & wise and may be working in the field of Finance or Management in Foreign Lands. Here, Wealth increases manifold as Jupiter expands the things related to where it sits. So, in Taurus, the sign of Wealth, it expands the wealth. At the same time, spouse will be very religious and someone fond of performing all the rituals. A great amount of wealth of knowledge is on the cards. Spouse is like a Guru for the native.

Virgo Ascendant - If it is Virgo Ascendant, Jupiter rules 4th & 7th house and sits in 12th house in Leo. Here, Spouse is very Spiritual in nature. They may not a ritualistic here. The difference between Religious and Spiritual is like Searching God in Books Vs Searching God within. Here, spouse brings Spirituality and Spiritual Values in the life of Native. These people are very creative, as Jupiter expands Leo's Creativity. Their creativity will flourish and give results in Foreign Lands or Isolated Places. They can also work as people behind the Scenes like Directors of a Movie.

Saturn - Saturn also can be 7th house ruler through its two signs.

In either sign (Capricorn/Aquarius) as 7th house lord, Saturn in 12th house (for Cancer/Leo Ascendants respectively) shows that access to foreign lands or foreign travels came late in life. In early life, they may have tried a lot to reach to foreign lands but their may be one or the other obstacles. Saturn in Gemini for Cancer Ascendant shows someone in Service of others in Foreign Lands in the field of Communications, most probably in MNCs. It also shows that person is frugal or miser and doesn't spend a lot. Saturn in Cancer for Leo Ascendant shows a healer and someone who has some issues running with mother. It also shows a Lawyer or Judge in Foreign Lands. With Saturn in Cancer in 12th house, it seems that it will be the case of obstacles or disputes in marriage as Saturn being a malefic planet is 7th lord and is sitting in 12th house in not so good dignity. Saturn ruling the 7th house is generic position for a delayed marriage. Again, any other yoga or dasha can change the scenario totally.

Rahu - If Rahu is 7th house Lord through its sign Aquarius, as it co-rules Aquarius along with Saturn, and sits in 12th house in Cancer then 1st of all we need to make sure of Saturn's position as it is the main ruler. Rahu in Cancer in 12th house will transform Rahu as Moon as Rahu changes its nature as per the lord of sign it is placed in. At the same time, Rahu's basic nature of being insatiable will remain there. Rahu in Cancer in 12th house basically indicates that this native/spouse will be extremely emotional. But as Rahu remains a malefic energy, it may show that someone using emotions for some hidden gains. This position will certainly link spouse to foreign lands as Rahu too represents Foreign Things. Rahu in 12th house shows person is kind of spendthrift. He is unable to save anything. But this position shows huge karma with foreign lands.

Ketu - Likewise, If Ketu is 7th house Lord through its sign Scorpio, as it co-rules Scorpio along with Mars, and sits in 12th house in Aries then 1st of all we need to make sure of Mars' position as it is the main ruler. As Ketu isolates/separates a person/spouse from the things related to the house Ketu is sitting, here it separates person from the spiritual beliefs spread by others. They never find themselves agree with the concepts of spirituality of others and always find fault there. Similarly, they reach foreign land but don't find anything of interest there and feel isolated. It is one of the most prominent Moksha Margi position. Ketu in Aries shows that these people will always assert their individuality in Spiritual matters. They will assert that they have the best spiritual concepts.