Use your trackpad to zoom in on an image
You can use your trackpad to zoom in on part of your screen.
Choose Apple menu > System Preferences, click Accessibility, then click Zoom.
Select “Use scroll gesture with modifier keys to zoom” to turn on zooming, then choose Control, Option, or Command from the pop-up menu.
Set additional zoom options:
Select “Smooth images” to make the zoomed screen images appear smooth.
Select “Zoom follows keyboard focus” to make the zoomed image shift to follow your cursor.
Click the “Zoom style” pop-up menu, then choose Full screen or Picture-in-picture.
When screen zoom is turned on, press and hold the modifier key and scroll using the trackpad to enlarge and reduce the screen image.