i need to lock my phone because it got stolen

If your iPhone, iPad, or iPod touch is lost or stolen - Apple Support

brynhildurmelot wrote:

I have been trying to lock my phone because it got stolen and it doesn't work, what can i do?

What happens when you try?

If you had a strong passcode on the device, it's already locked.

see >>> https://support.apple.com/en-ca/HT201472

brynhildurmelot wrote:

It's not

Then your device will remain locked. The holder of your device can of course, reset the passcode, but that will erase your data.

If you had Find My enabled, the device is also activation locked, so can never be used unless you remove it form your account.

brynhildurmelot wrote:

So if i have a passcode they won't get into it?

I can't tell you that.

If your passcode is easily guessed, it's of no value.