In what book of the Bible does it command brides to shave their heads and manicure their nails?

It is the book of Deuteronomy.

I does not really command the brides to shave their heads and manicure their nails. This is a reference to a special situation.

If one of the Israelites wanted to marry a captive woman the the man was to bring the girl to his home, shave her head ,pare her nails and give her time to lament for her family for a whole month. Only then could he marry her officially and the lady would become his lawful wife. ( Deuteronomy 21:10-14)