In order to use features such as the Offline mode and Camera search, you would need to allow them permission to access your device's storage and camera.
Usually, a banner appears every time to ask you, but just in case you have denied that permission at first, you can restore it following a few easy steps.
Go to your Device Settings, scroll down and tap on "Apps". After that, tap on the app of choice, scroll down and tap on "Persmissions".
Depending on which feature, you would like to allow permission to, you can choose "Camera" and "Storage". Finally, choose "Allow".