hello guys could you please advice me, I have a iphone 7 plus and now my iphone has a stolen I want to lock that iphone how to I lock her

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

If you had Find my iPhone enabled before it was stolen, go to https://icloud.com/find and put the phone in Lost mode.

If you did not have Find my iPhone enabled and you did not have a lock code on it kiss your phone and all of your personal data goodbye. Time to change all of your passwords and cancel any credit cards stored on the phone.

Hi,

Follow the instructions in this Apple support article > If your iPhone, iPad, or iPod touch is lost or stolen - Apple Support

Lost or Stolen

http://support.apple.com/en-us/HT201472