Enter Whoscall and tap on "⋯" on the top left corner.
Click on the "Setting" on the menu page and enter "Backup your app data".
Click on ""Back up now"". If you have already turned on iCloud in the Setting, after clicking on the ""Backup now"" button, it will start the process to back up the data. If you haven't turned on iCloud in the Setting, please follow the instructions to turn on iCloud to finish the backup process.
The ""Save the cipher key"" page will show the password to access the backup data. Please safekeeping the password so that when you change a new device in the future and have to restore the backup, you'll need the cipher key to restore it. *Whoscall will not access or save the cipher key out of consideration for your privacy and security.
After properly saving your cipher key, the backup process is completed.