my iphone

Step 1: Prepare your iPhone for restoration
Connect your iPhone to your computer via USB and click the gray Back Up Now button when viewing the Summary tab for your given device in iTunes. Alternatively, follow our guide on how to use iCloud to back up the device you Apple’s remote servers. Although backing up your device is not necessary, doing so will store your photos, apps, contacts, settings, and other data so you can automatically restore other iOS devices from the backup down the line.
Step 1: Access the Reset menu
Tap the main Settings icon when viewing the homescreen, select the General option on the resulting menu and tap the Reset button at the bottom of the next page.
Step 2: Reset your iPhone  
Tap the blue Erase All Content and Settings option second from the top, followed by the red Erase iPhone option in the resulting pop-up window to confirm the decision.
Step 3: Ensure the phone was restored
Once the restoration process is complete — a process that may take up to several minutes — check to ensure the phone has been restored to the original factory settings. If done correctly, you’ll once again be presented with the iOS Setup Assistant upon startup, from which you can then restore your phone from backup or continue the process as if setting up a new phone entirely.