OS X El Capitan now comes with Split View window resizing. Split View makes it easy and fast to put two applications side by side in full-screen view. This can be a big help if you need to copy and paste text between applications.
There are two different ways you can use Split View window resizing in OS X El Capitan.
Here’s the first way:
1. Click and hold the green fullscreen button in the upper left corner of an application window.
2. Release your trackpad or mouse button to put the window on the left side of your screen or drag it over to the right side if you prefer.
3. Click on one of the other app thumbnails that will appear on the opposite side of the screen to open it side by side with your first application.
The second way involves Mission Control:
1. If you are already running an app full-screen, just open Mission Control.
2. Drag the other app you want to the desktop of the first app at the top of the Mission Control screen and drop it.
3. Then click on the desktop at the top of the Mission Control screen that has both apps running on it.
When you are done with Split View, just hit the Escape button or click on the green full-screen button.
Once you have the application windows side by side, you can also resize them so that one app has more screen space than the other.
Here’s how you can resize Split View apps running side by side:
1. Just place the cursor in the middle of the two apps until you see the divider icon appear.
2. Click the divider and resize the window until it's the size you prefer.
For more about Split View window resizing, see the original tip.