FOLLOWING STEPS ARE NECESSITATED
1. Connect your device with your computer.
2. Open iTunes, on a Mac with macOS Mojave 10.14 or earlier, or on a PC.
3. You must follow the onscreen steps when prompted for your device passcode or to Trust This Computer.
4. Open finder on a Mac with macOS Catalina 10.15.
5. You are to locate your device on your computer, however in case you don’t find then go for guidance.
For saving Health and Activity data from your device or Apple Watch, you are to encrypt your backup:
Select the box called Encrypt [device] backup and create a memorable password. In case you don't need to save your Health and Activity data, proceed with backup that isn't encrypted. Just click Back Up Now.
Write down your password and store it somewhere safe, because there's no way to recover your iTunes backups without this password.
Backup With iTunes