Folding ones Tallis:
One is to fold his Tallis on Motzei Shabbos [immediately upon returning from Shul]. [It is proper to personally fold one’s Tallis rather than give it to someone else to fold. If one forgot to fold his Tallis immediately on Motzei Shabbos, then the next day prior to wearing the Tallis one is to shake it towards the ground.]
Sparks of Kabala
The reason one is required to fold his Tallis immediacy after Shabbos is because the Kelipas attach themselves to the Tallis prior to it being folded, and this is a great danger. This applies even during weekdays after Shacharis that one should fold his Tallis immediately after prayer rather than leaving it rolled up.
Segula for one’s wife:
Folding one’s Tallis on Motzei Shabbos is a Segula for one’s wife to merit long years.
 In order to begin doing a Mitzvah immediately after Shabbos .[ibid]
See Admur ibid which mentions this in connection with those who are accustomed to have a special Tallis for Shabbos.
 Admur [brought in previous footnote] writes “immediately” after Shabbos.
Should one fold the Tallis before or after Havdala? There is a difference of opinion in whether it is to be done before Havdala or after. The Yaavetz in his Siddur as well as Kitzur Shlah write to fold it before Havdala, after Maariv. However the Lekutei Mahrich, Derech Chaim and Darkei Chaim Veshalom 468 record it is to be folded after Havdala.
 Ben Ish Chaiy Noach 16; Nemukei Orach Chaim 24
 Midrash Talpiyos brought in Taameiy Haminhagim 424; Ketzos Hashulchan 100 footnote 6
 Kitzur Shlah; See Tamei Haminhagim 424
 Taamei Haminhagim KU”A Ishus p. 7