In Jewish tradition, there are seven women identified as prophets (Sarah, Miriam, Deborah, Hannah, Abigail, Huldah, and Esther). Concerning Huldah, we know of only one of her prophetic acts, when she gave advice to King Josiah (2 Kings 22–23; see also 2 Chron 34).
However, this single piece of advice was extremely important; it guided Josiah to undertake the thoroughgoing reforms of religion in Judah that characterised his reign. “Josiah took away all the abominations from all the territory that belonged to the people of Israel, and made all who were in Israel worship the Lord their God. All his days they did not turn away from following the Lord the God of their ancestors” (2 Chron 24:33).
Huldah’s husband, Shallum, had a prominent position in the royal court. He was the keeper of the king’s wardrobe (Jer 34:5); he therefore had daily access to the king and was able to meet him in relative privacy. He was better placed than most to talk with the king and advise him. Huldah was therefore among the inner circle surrounding King Josiah.
According to rabbinic tradition, Huldah was a relative of Jeremiah (Megillah 14b). The last thing said in Hebrew scripture about Rahab and Joshua is that “Rahab the prostitute, with her family and all who belonged to her, Joshua spared; her family has lived in Israel ever since” (Josh 6:25). The rabbis, however, maintain that Joshua and Rahab married, and that their descendants included Hilkiah, Jeremiah, Huldah, Seraiah, Mahseiah, Baruch, and Ezekiel. That’s quite a family!
The significance of Huldah is that it was she, a woman, who was consulted by the king, and she, a female prophet, whose guidance led to a pivotal reform in Judah. Claude Mariottini writes that “Huldah’s oracle is significant because she is the only woman prophet who proclaimed a message about future events. She begins her speech, like the other male prophets, claiming that her words were the words of God: ‘Thus says the Lord, the God of Israel.’ This expression is the messenger formula that was used by the Old Testament prophets to introduce their oracles. As a prophet, Huldah saw herself as a messenger of God set apart to speak in God’s name.” (see https://claudemariottini.com/2013/09/17/huldahs-oracle/)
Josiah reigned from 640 to 609 BCE, with the reforms noted above taking place during the late 620’s. What drove the reforms was the discovery, in the midst of the restoration of the Temple, of an ancient book of the Law, at the bottom of a money chest that had recently been raided to pay for renovations to the Temple (2 Ki 22:8–10). The book set out the requirements of the Law; Josiah panics because he realises that the nation has not been faithful to the covenant, and that God will punish them.
Josiah repents in contrition, consults with Huldah, and then implements extensive reforms. Many scholars believe that the book referred to in 2 Kings 22 could well have been what we know as a Deuteronomy, which literally means “second law”. This book was supposed to have been lost during the wholesale destruction of anything to do with worship of the Lord God, from the previous two kings, who were hostile to worship of Yahweh during their reigns.
Did the fact that the consultation with Huldah is reported without any “excuses” or “explanation” mean that there were female prophets at the royal court, as a matter of regular practice? The group that came with Kimg Josiah included the priest Hilkiah, two men identified as “Shaphan the Secretary and the king’s servant Asaiah”, as well as the sons of Shaphan and Micaiah, obviously another court official. This was an impressive group of high-status people.
Later tradition claims that Huldah proclaimed her prophecies at a place in Jerusalem now called Huldah’s Gate. The main theme of the incident involving her could be seen to be, “listen for God’s voice, wherever it comes from”. You can read the rabbinic traditions about Huldah at https://jwa.org/encyclopedia/article/huldah-prophet-midrash-and-aggadah