If it's simple text, I'd copy-and-paste the content into an Event (you have to create it first :-( ) or add the file's URL to the Event. But AFAIK Lightning doesn't let you attach files to Events. If you do insert an URL, you may have to think about placing the linked document somewhere where you can get at it regardless of your location. Google Docs, Dropbox or similar, perhaps. MS products do enjoy tight integration, but then each is privy to the innermost workings of its stablemates and they can use proprietary protocols and interfaces to communicate with each other. OTOH, they don't share too easily with third party software. If that degree of tight integration is important to you, you need to decide for yourself if it's worth paying for. Speaking for myself, I am mean; I'm happier with a hotch-potch of not-very-well-integrated free open source tools. Thunderbird, Firefox, Libre Office. Oh, and Linux. ;-)