As of 2014, you can wipe an iPhone's memory by going to the setting's menu, tapping on General, tapping the Reset button, and choosing Erase All Content and Settings. Depending on your iPhone model, the memory wipe can take between a few seconds and two hours.Continue Reading
The icon has a picture of gears and is located on the home screen by default. Sync your iPhone to your computer first if you want to back up your data. Plug in your iPhone to make sure it doesn't run out of power during the memory wipe.
Tap the General icon, which is located in the Settings menu and looks the same as the Settings icon.
The Reset button is located at the bottom of the General menu.
To delete all the data on the iPhone, including music, movies, applications and preferences, select Erase All Content and Settings. After selecting this option, there is a confirmation menu that includes a time estimate for the process. Tap Erase iPhone. For the iPhone 3GS and subsequent models, the process takes a few seconds because of how the flash memory is encrypted. Older iPhone models released prior to 2009 take much longer.