Is there havdalah from Shabbos to YT and YT to Shabbos? If so, what is said and what isn’t said?
There are two type of services that we say at the beginning and ending of holy days, such as Shabbos or Yom Tov. We say kiddush- (lit. to sanctify) at the beginning of a special day, to proclaim that this time is holy and special, and havdalah -(lit. to seperate) at the end of the day when we go from a time that is more kadosh (holy) to a less holy time. We are then saying that the previous time was holy and differant then the time that we just entered. This is why we say havdalah when we go from Shabbos to the weekdays. Similarly, we say a sort of havdalah when going from Shabbos which is more kadosh to Yom Tov which is less. In the other direction though, when going from Yom Tov to Shabbos we don’t say havdalah, rather we only say kiddush, because we are going up in kedusha . It should be noted that when going from Shabbos to Yom Tov, we are saying a sort of mixed service, because we now have to say havdalah because we left the holiness of Shabbos, and kiddush to santify the Yom Tov, that is why we say a special type of kiddush when Yom Tov is on motzei Shabbos. You can see this special kiddush/havdalah in many siddurim or machzorim.