The Prophet (ﷺ) was ordered (by Allah) to prostrate on seven parts and not to tuck up the clothes or hair (while praying). Those parts are: the forehead (along with the tip of nose), both hands, both knees, and (toes of) both feet.
Sahih al-Bukhari Book 10, Hadith 204
← Previous Hadith Hudhaifa said, "I saw a person not performing his bowing and prostrations perfectly. When he completed the prayer, I told him that he had not prayed." I think that Hudhaifa added (i.e. said to the man), "Had you died, you would have died on a tradition other than that of the Prophet (ﷺ) Muhammad."

Sahih al-Bukhari Book 10, Hadith 203 Next Hadith → The Prophet (ﷺ) said, "We have been ordered to prostrates on seven bones and not to tuck up the clothes or hair."

Sahih al-Bukhari Book 10, Hadith 205