Does a kallah, the daughter of sefardi mother and ashkenazi father, needs to follow the minhagim/halachah of her father or husband, or can she choose to follow her mother’s minhagim? For instance, the question might be relevant to hair covering: although ashkenazim use a pe’ah, Rav Ovadia Yosef has ruled that it is assur. Can she choose what she prefers?
As a general rule, a person — man or single woman — should follows the customs of his father, which determines which liturgy one uses for prayer, which script is used for mezuzos, various issues of chumros for tereifos, and all the many differences between Ashkenazim and Sephardim (and sub-groups within them). After marriage, a woman follows the custom of her husband, and may not go against his will based on the custom of her parents (or other customs).
Sources: Iggros Moshe, Even Ha’ezer 59; Om Ani Chomah, Even Ha’ezer 21.