Is there any way to lock an iPhone app? So, people don't get in it?
No but you can lock you phone so people can't get in it peried.
I don't think so but try settings.
no. there's isn't.
Not for any third party apps, but you enable restrictions on apps like camera, youtube and safari. You can enable these in the restrictions menu in the general settings.
If you have an jailbroken device you can get an app called ilock
Uh jus lock your phone
Jailbreak your iPhone and install one app named iProtect. Then you can set password on any apps you want.