The Gemara in Masechet Shabbat (32) discusses the unique importance of the Mitzva to light Shabbat candles before the onset of Shabbat. This Mitzva is afforded such significance that the Mishna (31b) lists negligence with regard to Shabbat candles as one of the three sins for which a woman is punished with complications during childbirth, Heaven forbid.
This Mishna obviously assumes that the obligation of Shabbat candles rests specifically upon the woman. The Shulhan Aruch (263:3) explains that since the wife generally spends more time at home and takes responsibility for all the household needs, the Rabbis assigned her the primary obligation of Shabbat candle lighting. Although the Mitzva is fulfilled even if the husband lights the Shabbat candles, he nevertheless should not usurp the wife's Mitzva, and should rather allow the wife to perform this Mitzva. However, as the Arizal (Rabbi Yishak Luria, Israel, 1534-1572) famously established, it is proper for the husband to participate by preparing the candles for the wife's lighting.
The Kaf Ha'Haim (commentary to the Shulhan Aruch by Rabbi Yaakov Sofer, 1870-1939; listen to audio for precise citation) writes that before a woman lights the Shabbat candles, she should give some money to charity. She should recite a special "Le'shem Yihud" prayer (which the Kaf Ha'Haim cites) before setting the money aside, and then recite another "Le'shem Yihud" before lighting the candles. Immediately after she lights the candles, she should recite a special prayer (which appears in many different Siddurim and Zemirot booklets) that her children should grow to become accomplished Torah scholars and men of piety. The Shabbat candles represent the human soul, as indicated by the famous verse in the Book of Mishle (20:27), "A person's soul is the candle of God." Women thus pray that in the merit of their kindling of the Shabbat lights their children's souls shall "shine" with the light of Torah. This prayer includes as well a request on behalf of the husband, that he should enjoy a long life of happiness and success, particularly in earning a respectable livelihood and in serving the Almighty.
The Kaf Ha'Haim concludes his discussion by noting that women should be dressed in their Shabbat clothing at the time of candle lighting. Many times, particularly in the winter months, when Shabbat begins early on Friday afternoon, women are rushed and do not dress in their Shabbat clothing before candle lighting. The Kaf Ha'Haim instructs that every effort must be made to ensure to bathe and don Shabbat garments already before the lighting of the Shabbat candles.
Summary: Although the obligation to light the Shabbat candles applies to both men and women, it is directed primarily to women, and therefore a husband may not insist on lighting the candles in his wife's stead. Before lighting the Shabbat candles, a woman should dress in Shabbat clothing and set aside some money for charity. After lighting, she should recite the special prayer asking that God bless her with children who become Torah scholars, and bless her husband with long life and success.
