Regarding some of the Halachot that apply to Tefilat Musaf on both days of Rosh Hashana. Being that Rosh Hashana is also Rosh Chodesh, Halacha says that it is proper, in the text of Musaf to say ‘Viet Musfe’ (in plurality), to include the two Musafim, the Korban Musaf of the Holiday, and the Korban Musaf of Rosh Chodesh. The question is, what if a person makes a mistake and says ‘Viet Musaf’ (non-plural)? According to the Halacha, he fulfilled his obligation Bediavad (in the least manner acceptable). Now this year, specifically that it falls out on Shabbat, so you have a definite ‘Musfe’, because you have Rosh Hashana, and you have Rosh Chodesh, and you have Shabbat. So you have 3 reasons why you say it in the plurality.
But still, Rav Chida holds that if you make a mistake, and even on Rosh Hashana Shabbat, like this year, and you make a mistake and you say ‘Viet Musaf’, then still, Bediavad you are OK. But, one should be careful. Use the Machzor, and when you get to that section, be careful not to say what is normally said in Musaf Shabbat or Rosh Chodesh where you say ‘Viet Musaf’. Make sure to say on both days of Rosh Hashana, ‘Viet Musfe’.
There’s also a question regarding ladies and Musaf. Do they have to pray Musaf? The Halacha we hold all year long is that ladies are exempt from praying Musaf. And more so, it would be proper that the ladies do not pray Musaf. Even when the ladies come to Shul, it would be better for them to listen to Musaf from the Shaliach Tzibur (Chazan), as opposed to saying it themselves. Shacharit they could pray, but Chacham Ovadia Yosef holds, that they shouldn’t pray Musaf. However, on Rosh Hashana, since the Musaf is filled with Pisuke Rachamim, especially the three most important sections of Malchuyot, Zichronot, and Shofarot, and since this Musaf is of supplications and special prayers, so therefore it would be permissible for ladies to pray Musaf on Rosh Hashana. And it would even be advisable to do so. So, even those ladies that have the custom not to pray Musaf all year long, which is correct, they should pray the Musaf on the two days of Rosh Hashana.
