Instructions
Open the "World of Warcraft" launcher and click "Play."
Type your account name and password on the "World of Warcraft" login screen and click the "Login" button.
Select the realm you want to play in, choose your character and click "Enter World."
Open the "Options" menu by pressing the "Escape" key once you are in the game.
Click the "Video" button.
Select the "Resolution" option on the "Video" window.
Click the "Use UI Scale" check box if it isn't already checked.
Click on the "UI Scale" slider and drag your mouse to the left to decrease its scale. Click the "Apply" button to view your changes.
Click "OK" and then press the "Escape" button to exit the "Options" menu. Your action bar will now be smaller.