1.Tap Phone > Keypad tab.

2.Tap More options > Settings.

3.Tap Call > Voice over LTE settings.

4.Tap Use VoLTE when available or Do not use VoLTE.

Step 2 : Step 2: You will then be taken to the main screen of the app. Under the Privacy tab, scroll down to find a list of applications that you can lock. Tap on the app name that you want to lock. The first time you lock an app, you will be prompted to grant App Lock Usage data access.

Step 3: Press the back button to go back to the main menu of App Lock. Now, you can lock any app that you want by simply tapping on the lock icon near its name. At this point, if you try and open any locked application, App Lock will prompt you to enter the unlock pattern that you first created. To make the app use the fingerprint scanner for verification purposes, head over to the Protect tab and enable the Fingerprint lock option.

Step 4: After completing all these processes you will see a app welcome screen. Read the instructions if you want and click Next.

Step 5: On the main screen you will see a "+" button. Tap on that and Select the Images or Videos you want to hide.

And you will see a confirmation message on your screen as shown in the Image below.