You cannot. They will have already taken it off and taken out your SIM
Change as many of your passwords as you can,
Please look at this Apple article and my additional advice below it:
If your iPhone, iPad or iPod touch is lost or stolen – Apple Support (UK)
Tracking lost or stolen phones
The 'Find My' tracking is to help you discover if you left your phone in the office or the restaurant. Lost or Stolen phones are rarely ever seen again.
Risk mitigation
Get your provider to
Cancel your SIM.
Send you a replacement SIM on same number.
You can then put the SIM in another iPhone to get the codes you will need.
Phishing warning
Its possible for a thief to obtain your phone number particularly if you did not have a PIN set on the SIM. So do not respond to texts to sign into your account! They are NOT from Apple!
Recognize and avoid phishing messages, phony support calls, and other scams - Apple Support (IN)