Use a screen saver on your Mac
You can use a screen saver to hide the desktop when you’re away from your Mac or if you need extra privacy.
On your Mac, choose Apple menu
> System Preferences, click Desktop & Screen Saver, then click Screen Saver.Click a screen saver on the left, then set options for how it will look on the right.
The options available vary depending on the screen saver you selected.
Source: Click the pop-up menu, then choose the pictures to show in the screen saver. You can use pictures that come with macOS or choose pictures from your Photo Library or another folder.
The preview area shows how the screen saver will look; give it a moment to preview your selection.
Shuffle slide order: Select the tickbox to show pictures in a random order instead of their order in the source.
Screen Saver options: Click to set options for colour, speed and more.
Set options for when to show the screen saver.
Start after: Click the pop-up menu, then select the amount of time you want your Mac to wait before starting the screen saver.
Show with clock: Select the tickbox to show the time in the screen saver.
Use random screen saver: Select the tickbox to let macOS choose which screen saver to use.
Hot corners: Click to set a shortcut for quickly starting the screen saver whenever you need it.
To stop the screen saver and return to the desktop, press any key, move the mouse, or touch the trackpad.
If you want more security when you stop the screen saver, see Require a password after waking your Mac.