Ask is an interesting verb which several different usages with subtle and not so subtle difference between them:
1) Ask for (means ask someone to give you something, request for something).
Examples:
i) I asked my father for money.
ii) Sudhir asked for leave.
iii) The cop asked for his driving license.
2) Ask (without for) means ask for information, request someone to tell you something.
Examples:
i) Suman asked the way to station.
ii) Don’t ask me the dates. I don’t remember them.
iii) Sanjeeev asked what day it was.
3) Sometimes, ask comes with two objects – one stands for who the request is made and the other one for what the request is made for.
Examples:
i) Sanjeev asked his father his date of birth.
ii) You can’t ask questions to the quizmaster.
iii) He asked his boss for leave.
iv) Ask the officer for a reason why he is not forwarding your application.