Most phone that shipped from outside country do lacks the internet setting of the present country due to their APN difference.
this activation can be possible if your phone has WAP, WEB or GPRS that shows that your phone has the facility to browse
#1. For MTN scroll to message and type SETTING send to 3888 you will immediately receive a message with a code then follow the instruction you will be connected.
#2. For GLO text the type of phone without a space,model of the phone and send to 927 Eg Nokia 6230 and send to 927.
#3. For Airtel go to message and text INTERNET space type of phone space model of phone and send to 232 eg Internet Nokia 6230 and send to 232.
#4. For 9mobile Go to message and type SETTINGS and send to 790.