You can restrict local access to Files Pro by setting a Passcode Lock. Once you have set a Passcode Lock anyone attempting to start Files Pro on the iPhone will need to enter your 4 digit passcode to gain access to your documents.
To enter a Passcode Lock, tap the gear icon at the top left of the screen to display the settings, then tap the Passcode Lock item under Local Access.
You will be prompted to enter and confirm a 4 digit numeric passcode. Next time you, or anyone else, starts Files Pro you'll need to enter this code to gain access to your Files Pro.
To switch off the Passcode Lock go to settings, tap Passcode Lock, then tap Turn Passcode Off, you will be prompted for your passcode to authenticate the operation.
Turning Local Guest Access on allows anyone to view documents and folders located in your Public folder, without them needing to enter your passcode to unlock Files Pro. This is a convenient method of quickly viewing non-sensitive documents when you have enabled a Passcode Lock
Note: When Files Pro is started in local guest mode both local and remote users will only have access to the contents of the Public folder. To enable remote access to non-public documents and folders you must unlock Files Pro with your passcode.
If Lock on Wake is enabled you will be prompted for your passcode when the device wakes from sleep and Files Pro is running.