Smart phones contain most of our critical personal information such as photographs, e-mails, contacts. While giving away your old phone to a friend or selling it over an exchange offer you need to make sure that your information cannot be recreated by the new user.
It is thus suggested that you wipe out data completely before disposing off your phone. Here is how to go about it in simple terms:
Take a backup of your information on the phone
You may take a backup of your phone on to a personal computer using a data cable or You may also take a backup of settings and information using google cloud services
How to backup to google services?
Go to : Settings > Accounts and Backup> Backup and Restore
You may use the options to backup information to google services or services provided by your manufacturer
Applicable only for phones with Android 6 or earlier. After the backups are complete, it is not enough to wipe out data by resetting factory settings. Some of the data might still be recovered from your phone by an unauthorized user. By encrypting your phone, you will be making data recovery difficult without a password.
Go to: Settings > Security > Encrypt phone
Remove Account from the phone
Remove google accounts from your phone as these can be used to identify you or your gmail address
How? Go to: Settings > Accounts and Sync > Google > Select Account > Remove account
This will wipe out all personal and setup data from your phone and reinstate the device to the initial version.
Go to: Settings > Backup & reset > Factory Data Reset > Reset phone