Go to Settings > General and tap About.
Look for the serial number. You might need to scroll down to find the IMEI number
To paste this information into Apple registration or support forms, touch and hold the number to copy.
Tap “Settings” from the Home screen.
Select “System“ (This step might not apply on older tablets)
Scroll toward the bottom and tap “About phone“, “About tablet“, or “About device“.
Select “IMEI Information“.
The IMEI is listed on the screen.