Open Settings
Tap General
Tap About
Find the IMEI number in the device information list
Check the back of the iPad if the IMEI is printed there on some cellular models
Check the SIM tray on some cellular models
Connect the iPad to a computer and open Finder on Mac or iTunes on Windows
Select the iPad and view the device summary to find the IMEI
Dial *#06# on the iPad if supported by the model
Check the original box or receipt for the IMEI label