The Prophet (ﷺ) got his head shaved during Hajjat-ul-Wada`.'
Sahih al-Bukhari Book 64, Hadith 432
← Previous Hadith The Prophet (ﷺ) visited me during Hajjat ul-Wada` while I was suffering from a disease which brought me to the verge of death. I said, "O Allah's Messenger (ﷺ)! My ailment has reached such a (bad) state as you see, and I have much wealth, but I have no-one to inherit from me except my only daughter. Shall I give 2/3 of my property as alms (in charity)?" The Prophet (ﷺ) said, "No," I said, "Shall I give half of my property as alms?" He said, "No." I said, "(Shall I give) 1/3 of it? " He replied, " 1/3, and even 1/3 is too much. It is better for you to leave your inheritors wealthy rather than to leave them poor, begging people (for their sustenance); and whatever you spend for Allah's Sake, you will get reward for it even for the morsel of food which you put in your wives mouth." I said, "O Allah's Messenger (ﷺ)! Should I remain (in Mecca) behind my companions (who are going with you to Medina)?" The Prophet (ﷺ) said, "If you remain behind, any good deed which you will do for Allah's Sake, will upgrade and elevate you. May be you will live longer so that some people may benefit by you and some other (i.e. infidels) may get harmed by you." The Prophet (ﷺ) then added, "O Allah! Complete the Migration of my companions and do not turn them on their heels. But the poor Sa`d bin Khaula (not the above mentioned Sa`d) (died in Mecca) ." Allah's Messenger (ﷺ) pitied Sa`d for he died in Mecca.

Sahih al-Bukhari Book 64, Hadith 431 Next Hadith → During Hajjat-ul-Wada`, the Prophet (ﷺ) and some of his companions got their heads shaved while some of his companions got their head-hair cut short.

Sahih al-Bukhari Book 64, Hadith 433