My iphone got stolen and i have the serial number to find it i really need it

Did you enable Find My?

If you didn't turn on Find My [device] before your device was lost or stolen, it can't be used to locate your device. Change your Apple ID password. Change the passwords for other internet accounts on your device. This can include email accounts, Facebook, or Twitter etc...

Don'ts

If you remove the device from your account after you erase it, Activation Lock will be turned off. This allows another person to turn on and use your device.

Do's

• Mark As Lost.
• Erase your device.
• Apple Care+ :- file a claim for your lost or stolen iPhone. (If you had Find My enabled)

You can't locate your device using a Serial Number or IMEI number.