Originally Posted by
LIH Prem
Go to Settings/Messages and make sure you've enabled iMessage.
iMessage can only be used if you have Wi-Fi or cellular data switched on, which I usually do not because I have unlimited texting at no extra charge; and the only time I activate cellular data is if I have no Internet service...
...and if I want to download anything onto my iPhone, I simply do it at one of my Macintosh computers.