All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
Sahl ibn Sa‘d reported that a woman brought a woven piece of cloth to the Messenger of Allaah, sallallaahu ‘alayhi wa sallam, and said to him: "I have woven this sheet with my own hands for you to wear". He, sallallaahu ‘alayhi wa sallam, accepted it as he was in need of it. Later on he, sallallaahu ‘alayhi wa sallam, came out wearing it as a lower garment. Someone said: "How nice it is! Kindly give it to me." The people said (to that man): "You did not do well; The Messenger of Allaah, sallallaahu ‘alayhi wa sallam, wore it and he was in need of it, then you asked him for it though you are well aware that he, sallallaahu ‘alayhi wa sallam, never refuses a request." The man said: "I swear by Allaah that I did not ask for it to wear it. I asked him for it so that it would be my shroud after my death." Sahl (the narrator of this Hadith) said: “And, in fact, it was used as his shroud”. [Al-Bukhari].
This Hadeeth indicates the permissibility of preparing one`s shroud before death.
The Shaafi‘is choose the opinion that the individual should not prepare the shroud in his life time so that he avoids accountability for spending his money in such a matter that he does not need in the current time. The individual will be asked two questions pertaining to his property; from which sources he earned it and in which way he spent it. So, he should not buy the shroud in order to release himself of the second question.
The most preponderant opinion is the permissibility of preparing one` s shroud during his life with no dislike; for the approval of the Messenger of Allaah, sallallaahu ‘alayhi wa sallam, in the previously mentioned Hadeeth.
Allaah Knows best.