Anas b. Malik was asked whether Allah's Messenger (ﷺ) dyed his hair. He said: He had not become old enough to have white hair. Ibn Idris said that he had a few white hair. Abu Bakr and Umar, however, dyed hair with hina' (henna).
Sahih Muslim Book 43, Hadith 131
← Previous Hadith I saw Allah's Messenger (ﷺ) and there is one amongst the people of the earth who (are living at the present time and) had seen him except me. I said to him: How did you find him? He said: He had an elegant white color, and he was of an average height.

Sahih Muslim Book 43, Hadith 130 Next Hadith → I asked Anas b. Malik whether Allah's Messenger (ﷺ) dyed his hair. He said: He had not reached the stage when (he needed) dyeing (of his white hair). He had a few white hair in his beard. I said to him: Did Abu Bakr dye his hair? He said: Yes, with hina' (henna).

Sahih Muslim Book 43, Hadith 132