How do women convert to Judaism?

Answer 1

Jews have a ceremony called a Brit Bat (covenant of the daughter). Orthodox Jews have no ceremony for girls, but they say prayers for them.

Answer

According to Jewish law, a child (male and female) is Jewish if the mother is Jewish. There is no ceremony to bring them into the religion.

If your question is whether there is a female equivalent to a bris, outside of the US, a lot of Jewish families (at all levels of observance - Reform, Conservative, Orthodox) have a baby naming ceremony for girls where the baby is introduced to friends and family and her Hebrew name is announced.

Answer 2

Conversion is a life-changing and very serious undertaking and a potential convert should think it over carefully. It must not be done on a whim or because of temporary circumstances. One who converts is expected (from then on) to live as a Jew.
The first step would be, without outside help or influence, to get to know about Judaism. The person who felt interested should hang around a Jewish community in order to get a sense of whether Jews and Judaism as it is actually lived appeal to him/her. Also to do some reading. English-language books on Jewish thought and life can be found in Hebrew bookstores.
After that, the interested person would approach a Rabbi and ask about enrolling in a relevant formal course of study. This can last for several years and is an integral part of the process, since he/she will have to actually practice the religion.
Once that is completed, the convert immerses in a mikveh (ritual immersion); and, for uncircumcised males, undergoes circumcision.