How to put a password on iPhone 4?

How to put a password on iPhone 4?

Settings > General > Passcode Lock

1) Go to Settings
2)Go to General
3) Scroll down to Pass Code lock and click on it
4) Make sure Require Passcode Immediately is turned on
5) Choose either Simple Pass Code which is a 4 digit number combination

OR
6) slide the slider for simple passcode to off and it will allow you to enter in a word pass code