iPads are fine for documents but you will need the Pages app which is not free and for spreadsheet then you will require Numbers. I have a tablet (iPad) and a small laptop. The problem with a tablet is the size of screen bearing in mind that the onscreen keyboard takes up a significant chunk. Suggest that you go into a store and have a play with an iPad, or Samsung tablet and if possible a Nexus 10. Also suggest that you should be looking at the larger size tablets. However you may well be better off getting a small laptop. This will not have as good a battery life but will give you access to the full office suite and a dvd/cd player. A lot depends on your budget.
What is Amazon Go and will it come to the UK? The store without checkouts or queues