Different opinions exist as to whether a woman recites the Beracha over the Shabbat candle lighting before or after she lights the candles. The Shulchan Aruch (263:10) appears to follow the view of the Behag ("Ba'al Halachot Gedolot," Halachic work from the Geonic period), requiring that one recite the Beracha before lighting the candles. According to this view, Shabbat candle lighting is no different from any other Mitzva in this regard, and we should thus apply the general rule established in the Talmud that one recites the Beracha before performing the Mitzva.
However, the Rama (Rabbi Moshe Isserless, author of glosses to the Shulchan Aruch, Poland, 1525-1572) in siman 263:5, and the Ben Ish Chai (Rabbi Yosef Chayim of Baghdad, 1833-1909) in Paashat Noah, Halacha 8, held that one should first light the candles and then recite the Beracha. This was also the opinion Rav Hida in Mahazik Beracha, siman 263:4. Although it seems that even amongst the Sephardim there is a split regarding this Halacha, Hacham Ovadya Yosef in Yabia Omer, Helek 2, O”H:16, as well as in Yehaave Daat, Helek 2:33, prefers the opinion of Maran to make the Beracha and then light. Hacham Baruch Ben-Haim would say to the ladies, that they should follow whatever practice their mothers had.
It should be noted that there are opinions that say that a woman accepts Shabbat the moment she lights the candles. Therefore, she should ensure not to extinguish the match or candle after lighting, since the Shabbat prohibitions already took effect when she lit the candles (Shulchan Aruch 263:10.) Instead, she should place the match or candle on a surface and allow it to extinguish independently. It is therefore advisable to use a match, rather than a candle, to light the Shabbat candles, as matches extinguish must more rapidly than candles. (It is possible for a woman not to accept Shabbat through the candle lighting, and to accept it sometime later; the guidelines for how this is done will be discussed in a separate context.) See Menuhat Ahava, Helek 1, page 90.)
Summary: Different customs exist as to whether a woman lighting candles on Friday night should recite the Beracha before or after she lights the candles. Hacham Ovadya’s opinion is to recite the Beracha before lighting. After lighting the candles, the woman should preferably not extinguish the flame, but rather place the match on a surface and allow it to extinguish independently.
