The Prophet ﷺ did not raise his hands in any of his supplications except in the prayer for rain, when he would raise them so high that the whiteness of his armpits could be seen.
كان النبي ﷺ لا يرفع يديه في شيء من دعائه إلا في الاستسقاء، وإنه يرفع حتى يرى بياض إبطيه.
Bukhari narrated it in the Book of Rain-Seeking Prayer (1031), and Muslim narrated it in the Book of Rain-Seeking Prayer (7/895), both through Ibn Adi, from Saeed bin Abu Aruba, from Qatada, from Anas, and he related the hadith. The wording given is that of Bukhari, and Muslim's wording is the same, except that in the version transmitted by Abdul-Ala from Saeed, he said, "The whiteness of his armpit could be seen," or "the whiteness of his two armpits."Nawawi said in his commentary on Muslim, "The apparent meaning of this hadith might give the impression that he did not raise ﷺ except in the rain-seeking prayer, but that is not the case. Rather, it has been established that he raised his hands ﷺ in supplication on occasions other than the rain-seeking prayer, and these are too numerous to enumerate... " Then he said, "This hadith is to be interpreted as meaning that he did not raise his hands to such an extreme degree that the whiteness of his armpits could be seen, except in the rain-seeking prayer."