Hello! I do not own a iPad Pro myself but like all iPads its able to work with just the touch keyboard on the screen, it takes some getting use too if you have never used a touch screen keyboard before but its all down to what you prefer! Apple do a range of keyboards on there website and I'm sure more cheaper options are available,
Keyboards - iPad Accessories - Apple (UK)
Best advice is to play around with the iPad and find what works best for you! Hope you enjoy your new iPad, we are all here to help if you have any other questions