Final answer:
The E icon on an iPhone indicates a connection to the EDGE network, which is a slower data service compared to 3G or LTE.
Step-by-step explanation:
On an iPhone, when you see an E icon at the top of your screen, it designates that your device is connected to the EDGE network. EDGE stands for Enhanced Data rates for GSM Evolution and is considered a slower data network compared to 3G or LTE. It's particularly used in areas where higher-speed network connections are not available. Despite being slower, it allows for basic internet services.