How to prevent others from texting with your mobile phone?

Many mobile phones have the function of password setting, which is called PIn code. When the mobile phone is not used for a period of time, it will automatically lock, and it can only be used normally after entering the Pin code to unlock it. I wonder if your mobile phone has this function? If not, you can only take your mobile phone with you at any time and don't give others a chance to touch it.