I'm not a fan of the hot corner method of locking screen so here are 2 other ways to achieve screen lockage on MacOS / OSX:

Keychain Access: Toolbar Icon So You Can Click To Lock Screen

• CMD-space: Launch "Keychain Access"
• -> Preferences
• CHECK: "Show keychain status in menu bar"

Then you can lock screen by clicking the padlock on the Menu Bar and selecting "Lock Screen":

Automator and Keyboard Shortcut

Automator Service: Lock Screen via Applescript

First we have to bind an applescript to a service that starts the screensaver:

• CMD-space: Launch "Automator"
• File->New
• Service

• Change "Service recieves" dropdown to "no input"

• use search bar to search for "run applescript"

• Doubleclick "Run Applescript" to add it to the service.

• Copy/Paste this code into the Applescript box replacing any existing text:

• Save as: "Lock Screen"

Keyboard Shortcut

Next we bind a key to the new service.

• CMD-space: Launch "keyboard" (or System Preferences -> Keyboard)
• Shortcuts (top bar) -> Services (left pane) -> Lock Screen (right pane - scroll to find it)