How to put a lock on my iphone?

I'm not really sure what kind of iphone it is- it's more clunky than the newer ones, so I'm thinking it's the earlier one.

I've tried looking through all the stuff in my phone to see if I can lock it- but I can't find anything? Can you lock the old ones?

Yea setting general then pass code lock

If anything, you should find something in Settings > General > and then Passcode Lock.

1. Settings
2. General
3. Pass code lock
4. Turn pass code on
5. Enter a pass code

Go to settings, click general, scroll down and you'll see a bunch of different things one of them will say " Passcode Lock" click that and then follow the directions, hope this helps. Sounds like you have a iPhone 3G or 3GS. Is it round on the back or square if its round it is a 3G/3GS if its square its a iPhone 4/4s

Settins>General>Passcode Lock>Turn Passcode On

Then put what you want it to be.
:)