You can increase its security by locking individual apps on android phone and tablet. Remember, you have to increase the security of your phone by locking each app. People find it irritating when everything asks for a password. If you want to increase the security of your device, you must bear this irritation. Some apps in your gallery need a special password. Messaging and emailing apps hold private and sensitive data; therefore, you have to lock these apps. Android allows you to do this. Here are some simple instructions: