*#06# - IMEI (International Mobile Equipment Identity) number

*3001#12345#* and press call - Enter Field Mode. Information about the SIM-card, indicators of cellular communication and signal level. All data is constantly updated.

*777# and press call - Account balance for prepaid iPhone.

*225# and press call - Bill Balance. (Postpaid only)

*646# and press call - Check minutes. (Postpaid only). It will display you the available minutes of your talk time.

*#30# and press call - Calling line presentation check.

Apple iPhone 8 - secret codes. https://mobilespecs.net/phone/codes/..._iPhone_8.html