One of the biggest additions to iOS 8 is the customizable-keypad. While Apple's stock keyboard remains unaltered, you can now add a host of third-party keyboards/keypads and use it just as you would use the stock keypad.
All the third-party keypads come as apps (eg: SwiftKey, Swype, Fleksy etc.) You will download them from the App Store and then follow the steps to install/use them.
How to Add Third party Keyboards on iOS 8 for iPhone and iPad
Before you start this, you will need to have installed a third party keyboard. There are a bunch of them available on the App Store already.
Step #1. Open Settings
Step #2.Tap on General
Step #3.Scroll down, tap on Keyboard
Step #4.Now, tap on Add Keyboard.
Step #5.You should see a list of all the third-party keyboards you’ve installed. Tap on the one you want to add.
Step #6. Switch On the keyboard
Step #7. Quit the Settings app
Step #8. When the keyboard pops up, tap on the globe icon.
Step #9. This will cycle through all the keyboards you have enabled/added in the previous step.
Step #10. You can also do this: tap and hold on the globe icon and it will show a list of all available keyboards. You can slide over to the keyboard that you want to use.
How-to enable the third-party keyboard on iOS 8:
Notes: There are a few things you should note about third-party keypads in iOS 8.
#1. Third-party keypads can’t be used when you are entering sensitive data like credit card info or login passwords within Apple apps. This is to prevent the data you type from getting passed on to the developer (through the code).
#2. Some apps can prevent the use of third-party keypads within their app interfaces. Although this is not an option by default, app developers can disable third-party keypads for their apps by enforcing the stock Apple keypad. So, when you find that your Fleksy does not show up in an app, it could mostly be the app’s configuration (and not a problem with the keyboard app).
Watch out quick video to know how to add or delete keyboards from iOS 8: