Did you know that, Customize WordPress WYSIWYG Editor is one of my favorite excellent tricks by WP Engineer, please note this tricks need so many code to be added in functions.php on your theme, so read it carefully and happy explore this tricks.
Customizing the function of the buttons in your Editor
More Details about this tweak you can check it out on this post. If you found any problem about this tricks, you can leave on this post or directly from WP Engineer Author of this original Post.
Or if you want to quickest way, maybe you tried Adjusting the buttons via Customize WordPress Editor Plugin TinyMCE Advanced. Using plugin or written you own code? choose what make your happy 😉