Blockoban is the best puzzle game on iPhone.
WordFeud is the best free Scrabble game.
SpellTower, as mentioned, is awesome, probably the best word puzzle.
WordJong, because if SpellTower is the best then this is definitely the second best.
Enscripted, then, would be the third best.
Tetris is horrendous, don't let her download that.
Marblenauts
Save Toshi DX is lovely
Trainyard
Triple Town, kind of
Scribblenauts (words!)
Slice It!
Pathpix is a fantastic drawing-style puzzle
ORBITAL
Cat Physics and...
Cave Bowling, which are both excellent Donut games.
Cut the Rope, obviously.
You say she doesn't like action-oriented stuff but that's exactly what Tetris is, so you could try Zookeeper (and Zookeeper Battle) and ZONR, which might be up her street.