Start by installing the AppLocker app from the App Store on your Mac.

When you open the app, you’ll find a new icon in the menu bar. You’ll see a popup asking you to set a password. Here, click on the “Setup My Password” button.

From the Preferences menu, create your password (something that you won’t forget), and if you have a MacBook with Touch ID, you can also check the “Enable Touch ID” option. Now, click “Save Password” and then click on the red Close button in the top-left corner to exit the Preferences pane.

Go to the menu bar and click on the AppLocker icon. You’ll see in the dropdown that the app is locked. Enter your password and click on the “Enter” button to unlock the app.

Here, first check the “Start at Login” option. It will make sure that AppLocker starts up automatically every time you boot up your Mac and locks all your selected apps. Second, click on the plus sign (+) to add an app.

From the new window, search for an app on your Mac and then click on it to instantly add the program to the locked apps list.

Now, when you quit the app and try to launch it again, AppLocker will ask for a password.

Also, To Secure your macOS from virus and trojans, use always a mac optimization software like Mac Optimizer Pro.
visit:- https://macoptimizerpro.com/