The number three is widely recognized for a man’s shroud, but jurists differ over which pieces should make up those three. The Hanafi arrangement includes the qamis, whereas the reported Shafi‘i, Maliki and Hanbali preference is for three wrapping sheets without a distinct tunic.
The report of Aishah describes the Prophet ﷺ being shrouded in three white Sahuli cloths without a shirt or turban; other transmitted reports mention a qamis. This underlies a difference about preferred form, not the obligation to cover the deceased respectfully.