According to most poskim, women are not obligated in the mitzva of remembering Amalek, because this mitzva is connected to the mitzva of annihilating Amalek. Since women are not commanded to wage war, they do not need to remember what Amalek did to us (Sefer Ha-ĥinukh §603). Others claim that the mitzva to wage war applies to women as well, as they must assist the soldiers. Therefore, they too are obligated to remember Amalek. And even though the Sages established a fixed time for reading Parashat Zakhor – the Shabbat before Purim – it has no set time according to Torah law. In light of this, it is a mitzva that is independent of time, and thus women are obligated to perform it (Minĥat Ĥinukh ad loc.).
In practice, women are exempt from hearing Parashat Zakhor. Le-khatĥila, however, it is best for women to hear Parashat Zakhor, and many women do so in practice. A woman who finds it difficult to attend the services, but nevertheless wants to fulfill the mitzva, should read the passage herself from a ĥumash. After all, many authorities maintain that this fulfills the Torah commandment to remember Amalek. If there is a Torah lecture for women in the synagogue, it is permissible to take out a Torah scroll and read Parashat Zakhor for them. Even though no minyan is present, hearing Parashat Zakhor from a valid Torah scroll enhances the mitzva.
Therefore, le-khatĥila, women should hear Parashat Zakhor with a minyan. If that is impossible, someone should read it for them from a Torah scroll, without a minyan. If that, too, is unfeasible, they should read it to themselves from a ĥumash. While some Aĥaronim write that we do not take out a Torah scroll for the sake of women (Responsa Kinyan Torah 7:53; Halikhot Beitah 9:8), it is unclear what the problem is with this, since technically one may take out a Torah scroll in order to study from it. Some communities, therefore, have a custom to take out a Torah scroll and read Parashat Zakhor just for women.