SOME LETTERS OR ALL LETTERS
Finder treats what you enter as a pool of available letters. A result may use the whole pool or only part of it. With APPLE, the English list includes APPLE as well as PALE, LEAP, PEAL, PLEA, PAL and LAP. This is different from an exact anagram search: Finder keeps useful shorter results instead of requiring every tile to be spent. See the worked search.
Letter frequency still matters. APPLE supplies one A, one L, one E and two Ps. A candidate can use no more than those amounts unless a blank supplies a missing letter. This rack cannot make APPLY because it contains no Y. Type ? for a blank: A, P, P, L and ? can make APPLE, with ? supplying E. Each ? covers one missing letter; multiple blanks can cover multiple missing letters. Results show the completed word. Anagram requires the exact entered letters and does not treat ? as a blank.