To reverse mouse scroll on a Mac, click the Apple icon → click "System Preferences" → click the "Trackpad" or "Mouse" icon → click the "Scroll direction: Natural" checkbox to uncheck it.
Step
Method 1 of 2: Using the Touchpad (Trackpad)

Step 1. Click the Apple icon
It's the Apple logo in the top-left corner of the menu bar.

Step 2. Click System Preferences

Step 3. Click the "Trackpad" icon

Step 4. Click Scroll & Zoom

Step 5. Click the "Scroll direction Natural" checkbox to uncheck it

Step 6. Click the red "X" button
Mouse scroll settings will be saved.
Method 2 of 2: Using the Mouse (Mouse)

Step 1. Click the Apple icon
It's the Apple logo in the top-left corner of the menu bar.

Step 2. Click System Preferences

Step 3. Click the "Mouse" icon

Step 4. Click the "Scroll direction Natural" checkbox to uncheck it

Step 5. Click the red "X" button
Mouse scroll settings will be saved.