It's important to complete the instructions outlined below before you sell your phone:
If you are switching iPhone to iPhone
- Open Settings on your old iPhone
- Tap the Apple ID banner
- Tap iCloud
- Tap iCloud Backup
- Tap Back Up Now
- Turn your old iPhone off once the backup is finished
- Remove the SIM card from your old iPhone or if you're going to move it to your new one
If you are switching Android to Android
- Open Settings from the app drawer or home screen
- Scroll down to the bottom of the page
- Go to the System menu
- Tap Backup
- Make sure the toggle for Back up to Google Drive is set to On.
- Hit Back up now to sync the latest data on the phone with Google Drive
If you are switching operating systems
You can use apps in the Google Play Store such as move to iOS or third party apps such as Syncos Transfer.