Are the answers to both question forms (starting with 'how', and 'what') exatly the same? Is either choice more common in everyday English?
If you've never seen a person before, you ask, "What does she look like?" This is very general: "she's beautiful, she looks like a bit like her sister, she looks like an Olympic weightlifter, she looks part-Asian, etc."
If you do know what she looks like, you can still ask "How does she look?" Some typical answers are "she looks well, happy, excited to have won, a bit lonely, slightly better than yesterday ..." That is, "How does she look?" is not asking for a primary physical description.