And not an obligation on the garment - See previously in [in Mishah Berurah] Siman 17, Se'if Katan 5 what I wrote there.

Exempt from Tzitzit - Even though it says "and they shall make for themselves Tzitzit on the corners of their garments", nevertheless, from the fact that it says in another place "You shall make tassels on the four corners of your garment 'with which you cover yourself'", it is implied to mean specifically when you are covering yourself with it.

On the making of the Tzitzit - Meaning to say "at the time that he attaches them [the Tzitzit] on the garment". Rather, afterwards, when he wraps in it he makes the blessing of "to wrap". And if [the Tzitzit] became detached after he wore it, he is required to remove it [the Tallit] and make Tzitzit for it and to make the blessing when he wears it again... even if he will wear it immediately [after fixing it].

Only on his wearing of it - And the same law applies to Mezuzah. For we establish that the requirement is on the one who lives [in the house]. [And therefore] one should only recite the blessing on the Mezuzah when he enters to live in the house, immediately/right away. For then it is exactly similar to the [law of] wrapping [in the Tallit]...

It is exempt - The Achronim established that specifically according to the Rosh it is exempt [from Tzitzit] [as was written] previously in Siman 18 "a garment that is designated/used for nighttime, even if he wore it during the day [is exempt]". And [so] here too [in our case of shrouds], it is similar to the case of a nighttime garment since a dead person is exempt from mitzvot. But according to the Rambam who obligates a nighttime garment during the day, here too [by the case of shrouds] it is obligated. Therefore, for us (ie. the way we should conduct ourselves in this scenario), we should make Tzitzit for it, but not make the blessing on it. Garment merchants that wear [four cornered garments] with the intention to display to the buyers the garments size (ie. how it fits) are exempt [from attaching Tzitzit to the garment]. And if they wear it in order to avoid paying taxes on it, it's possible that it would be obligated in Tzitzit, like it is regarding Kelayim.