。
I asked her to send me the book.
Literal
Book [object-を] send-[for-me-てくれる] [in-the-way-ように] her [to-に] said.
~ように言う ('tell/ask someone to do X') is the standard pattern for indirect commands or requests. The subordinate clause 送ってくれる ('send for me') embeds both the action (send) and the benefactive (for me), so the combined phrase means 'told her she should send it to me.' に marks the addressee of 言う.