A factory reset allows you to erase the contents of an iPhone or iPad, useful if you are misbehaving or if you are selling it. Here is how to reset iOS.
Whether you sell your iPhone or take it for repair, you must reset it to delete your accounts and remove their content.
Factory reset an iPhone or iPad using Settings> General> Reset> Delete all content and settings. You will be asked to enter your password and your Apple ID before the end of the process.Also you can learn here how to unlock iphone 4 with easy steps.
How to soft reset an iPhone or iPad
If your phone has been locked and you learn how to restore iphone you just want to factory reset it but none of the buttons work, then press and hold the power button and the start button at the same time until the device turns off and you see the Apple logo. Then release it and your phone or iPad will return to normal.
Backup before restarting
There are times when you may want to reset the factory device not because you want to give it away, but because it is being played. Even if you use iCloud, before doing so, it is wise to make a full backup by connecting your iPad or iPhone to your computer, unlock it, wait for it to appear in iTunes and then click on it in the left panel. . You should open the Summary screen, where you will see a section of Backup copies. Just click on the Backup Now button. (Check the Encrypt iPhone Backup box if you want all your passwords saved).
Once this is done, the restart process can begin. It is also worth remembering to remove the SIM card before moving the iPhone or iPad, as it may have stored information and you may want to continue using it on a new phone or tablet.
The version of iOS you are using may affect what you see here, but they are all about the same, and things look the same on an iPad.
Step 1. Touch Settings, then General. Scroll down until you see Reset.
Step 2. Touch Clear all content and settings. Depending on whether you have established an access code and / or a restriction access code (they are different), you may need to enter that code or password to erase and reset it. There is no way to restart the device unless you enter the code (s).
Step 3. Now you must enter your Apple ID password. This is so that the account can be deleted from your device and Find My iPhone can be disabled. If you simply restore an iPhone through iTunes, you will be asked to enter the Apple ID and password when it restarts. Restoring it using the method we describe here will prevent the iPhone from requesting an Apple ID when it is restarted.
Step 4. The restoration process may take a minute or two, after which you will see the welcome screen that asks you to swipe to continue. Then it is ready to be sold or taken to an Apple store for repair.