Preparing children for bed on Shabbos

Hi,

One may not prepare for after Shabbos, on Shabbos.

However: One may put children into pajamas on Shabbos even if they will not go to sleep until after Shabbos, if there is any good reason - aside from a desire to make things easier after Shabbos - to do it now.

For example, one may change children into pajamas if their clothing is dirty, rather than change them into a fresh outfit and then into pajamas. One may also change children into pajamas if they normally wear pajamas for an hour or two before bed.

(Rav Moshe Feinstein, Igrot Moshe Orach Chaim 4:105:3)

Have a great rest of Yom Tov,
Mordechai