For additional security, you can set a personal identification number (PIN) as well as Face ID or Touch ID to access your account. To do this, follow these steps:

1. Tap Account
2. Select Security
3. Toggle "Enable PIN"
4. Enter a 4-digit PIN
5. Re-enter the same 4-digit PIN to confirm

You can change your PIN at any time by visiting the Security screen and tapping "Change PIN", which will require you to enter your current PIN to proceed. You can also enable Face ID or Touch ID via the Security screen, provided your device supports such features.