To protect data against unauthorized access, you must enable encryption of all data on the device (for example, account credentials, external devices and apps, as well as email messages, SMS messages, contacts, photos, and other files). For access to encrypted data, you must specify a special key – device unlock password. If data is encrypted, access to it can be obtained only when the device is unlocked.
Data encryption is enabled by default on password-locked iOS devices (Settings > Touch ID / Face ID and Password > Enable Password). Also, the hardware encryption on a device must be set to At block and file level (you can check this parameter in the device properties: in the console tree, select Additional > Mobile Device Management > Mobile devices, and then double-click the required device).
To encrypt all data on an Android device:
It is not recommended to use a pattern lock for unlocking the device. On certain Android devices running Android 6 or later, after encrypting data and restarting the Android device, you must enter a numeric password to unlock the device instead of a pattern lock. This issue is related to the operation of the Accessibility Features service. To unlock the device screen in this case, convert the pattern lock into a numeric password. For more details about converting a pattern lock into a numeric password, please refer to the Technical Support website of the mobile device manufacturer.