From the Apple menu, selectSystem Preferences.
In theSystem Preferenceswindow, choose theGeneralicon near the upper left corner.
Locate theShow Scroll Barsarea.
Your new scroll bar configurations are set.
These options will apply across all your Mac applications.
In macOS Catalina
The interface is a little different withCatalinathan earlier macOS and OS X versions.
From theSystem Preferenceswindow, selectAccessibility.
In the left sidebar, selectPointer Control.
Use the slider to adjustscrolling speed.
In OS X Lion Through Mojave
In the left sidebar, selectMouse & Trackpad.
To adjust your mouse or trackpad’s double-click speed, adjust the slider.
To adjust your mouse or trackpad’s scrolling speed, select theTrackpad OptionsorMouse Optionsbutton.
Enable or disable scrolling for your mouse or trackpad via the checkbox.
Close out of theAccessibilitywindow.
You’ve set your new preferences.
