How do I stop my Microsoft SwiftKey Keyboard from inserting predictions?

To turn off autocorrection, follow the below steps:

1. Open your Microsoft SwiftKey app
2. Tap 'Typing' 
3. Uncheck 'Quick prediction insert' and/or 'Autocorrect'

Please note this will not turn off the prediction bar. 

Read more: Can I turn off the Microsoft SwiftKey prediction bar?