Q: erased content to sell iPhone 5. new owner says in the set up she needs my Apple ID and password. Why

Erasing content doesn't remove the Apple ID. See this article:

What to do before selling or giving away your iPhone, iPad, or iPod touch - Apple Support

jaemiefrombroken arrow wrote:

 

I erased the content to old iPhone to give to a friend. She was setting it up tonight and says in the account section she needs MY Apple ID and password. Do I need to call Apple since it's registered to my account?

Only an assumption but I would guess that you left it locked so now she can't use it at all. Read the reply above this (Meg) for links to instruction pages on what to do now.