May one style their hair or undo the style on Shabbos?
It is forbidden for a woman to braid her hair on Shabbos, or to undo the braid. However she may split the hair [through the middle having the hair on the right part of the head brushed to the right and the hair on the left part of the head brushed to the left, thus having an empty path in the middle of the head].
Other Opinions: However there are opinions which forbid to split the hair [in the way explained above], which means to make the Sheitel, and so is the custom to forbid doing so using a vessel, however with a mere finger the custom is to be lenient.
Braid: It is forbidden to make a braid or undo a braid on Shabbos.
Split: Splitting the hair down the middle having the hair on the right part of the head brushed to the right and the hair on the left part of the head brushed to the left, thus having an empty path in the middle of the head, may be done only with a mere finger [as opposed to one’s hand].
May one make a hair do on Shabbos?
It is forbidden to make a hair do having it hold in place using clips and bobby pins. However one may enter bobby pins into the hair for mere orderliness and not for the sake of a design.
May one use a soft brush to make the above mentioned hair split?
May one use his hands to make the split?
No. One may only use a mere a finger.
May one use a comb to gather the hair and make it into a pony tail and the like?
No, one may only do so by hand.
Do the above laws of braiding and hair do’s apply equally to a Sheitel?
Yes, it thus may not be designed on Shabbos.
Does the hair design prohibition apply to men as well?
May one twirl his Peiyos on Shabbos?
It is best to avoid doing so.
Nevertheless some Poskim write that if they were already twirled before Shabbos then doing so does not involve a building prohibition. However one must take care to only do so with his hands while the Peiyos are dry and to not remove any hairs in the process.
Others rule that twirling the Peiyos is not at all within the building prohibition and may thus be done in all cases, so long as it is done softly with ones hands while the Peiyos are dry.
May one fold his beard on Shabbos?
 Michaber ibid
 Ketzos Hashulchan 146/11
 Rama ibid
 Due to the building prohibition. [Ketzos Hashulchan 146 page 39] However others explain that this is due to a suspicion that one may come to tear out hair. [Mishneh Berurah 303/84]
 Ketzos Hashulchan 146 page 40
 Piskeiy Teshuvos 303/8 in name of Minchas Yitzchak 1/80
 Piskeiy Teshuvos 303/8 and footnote 27
 Ketzos Hashulchan ibid
 As doing so even with a soft brush still contains the building prohibition.
 M”B 303/84
 As there is no building prohibition involved in splitting the hair and it was only forbidden due to suspicion that it may come to remove hairs.
 Ketzos Hashulchan 146 page 40
 Piskeiy Teshuvos 303/8 in name of Ketzos Hashulchan 146 footnote 21 [I have not found the source for this in the Ketzos Hashulchan there!]
 Piskeiy Teshuvos 303/9
 So writes Piskeiy Teshuvos ibid, and so is implied also from Ketzos Hashulchan ibid
 The Ketzos Hashulchan 146 p. 42 is Milamed Zechus that it does not involve a building prohibition as one is merely adjusting an already twirled Peiyos.
 So rules Beir Moshe 1/19 and 5/74
 Beir Moshe Ibid
 Ketzos Hashulchan 146 page 41
 As doing so is not considered a form of design. [ibid]