You have accomplished this task if you have activated encryption in your smartphone settings.
Encryption is a basic and very important setting that you should definitely activate. It is relevant for many different target groups and is always useful. In the event of theft or loss of the device, your data is more secure than without encryption. It cannot be read or changed so easily.
In Germany, many authorities have mobile forensic software such as Cellebrite. All your data, contacts, call logs, location data, login data and much more can be automatically collected via USB and displayed visually. This could be used to determine your identity and origin if your device is not encrypted.
Professional mobile forensic software such as Cellebrite can easily bypass most screen locks via the USB interface by exploiting security holes or trying to guess your pin. It is therefore essential that you activate encryption to protect your data and the data of your structures.
On most devices, the encryption does not differ visually from the normal screen lock. The first unlocking often removes the encryption on many devices so that you can use your device. Therefore, check in the settings whether the encryption is really active!
Please note that encryption is only effective when your device is switched off. In the event of loss or theft, this can happen when the battery is empty. Before you hand it over yourself, you should definitely switch it off!