Before you begin:
- Back up all your data, including contacts.
- Remember to remove the SIM card and any external storage such as a microSD card.
- Log out of services like email and social media, then clear the data from these apps if you can.
- Perform a separate encryption and wipe of data on the microSD card as well if you don’t plan to use the card in a new device.
- Keep the serial number of the phone or tablet on file for your records.
Encrypt your device before you are getting ready to wipe it. The encryption process will scramble the data on your device and, even if the wipe doesn’t fully delete the data, a special key will be required to unscramble it.
To encrypt your device on stock Android, enter settings, click on Security, and select Encrypt phone. The feature may be located under different options on other devices.
If the phone or tablet runs 5.0 Lollipop or later it may have Android device protection or factory reset protection (referred to as FRP) active.
This feature makes the phone unusable by a new owner if it’s been reset because they can’t activate it without entering a previously used Google account and password.
You’ll need to deactivate FRP if you plan to give the device away or transfer to another owner.
Wiping your device:
Skip straight to step 4 if you have a device running an earlier version of Android without FRP.
Step 1: First, turn off any screen locks. Go to Settings > Security or Lock Screen Security > Screen Lock and change the type to None.
Step 2: Remove your Google account from the device. Go to Settings > Users and Accounts, tap your account and then remove.
Step 3: If you have a Samsung device, remove your Samsung account from the phone or tablet as well.
Step 4: Now you can wipe the device with a factory reset.
For more information visit the Android help centre: https://support.google.com/android/
Apple devices that support iOS 5 or later include hardware encryption when you set a passcode. If you perform a wipe using the method below, the encryption key is also overwritten, which makes it very difficult for anyone who wants to recover the data.
Step 1: Before starting the reset process, make sure to unpair devices like the Apple Watch. Then, turn off Find My iPhone. For iOS 10.2 or earlier, go to Settings > iCloud > Find My iPhone. Enter your Apple ID password if prompted. For iOS 10.3 or later, go to Settings > Your name > iCloud > Find My iPhone.
Step 2: Turn off and sign out of other services including iMessage and the App Store. Go to Settings > Messages > toggle the iMessage option. For your Apple ID, go to Settings > iTunes & App Store > tap your Apple ID email address and then tap Sign Out.
For added peace of mind you may also want to sign out individually from any other linked services and apps, such as Facebook or Twitter.
Step 3: Sign out of iCloud completely. Head to Settings > iCloud and find Sign Out at the bottom of the page. For iOS 10.3 and later, Settings > Your name > Sign Out. For iOS 7 devices, choose Delete Account.
Note: if you delete all your data manually without signing out of iCloud, it will also delete the content from iCloud as well — which is something you don’t want to do.
Step 4: Start the wipe process. Go to Settings > General > Reset > Erase All Content and Settings. Confirm the selection.
Step 5: Remove the serial number of the device from your Apple account profile at appleid.apple.com.
For more information from apple visit: https://support.apple.com/en-gb/HT201351