@Laura2592 I've never done anything special, but I think some lights are nice, and maybe some non-religious festive decorations that wouldn't offend anyone who doesn't celebrate Christmas. An arrangement of pussywillows and rosehips, some snowflake decorations, that sort of thing-seasonal rather than specifically relating to Christmas. A Christmas tree isn't something that non-Christians do, so I'd skip that. And you could leave a bottle of wine or a box of chocolates wrapped up in some wrapping paper that isn't specific to Christmas.
And I don't think there's anything offensive about asking a guest, if you feel like it- "We were thinking it would be nice to decorate the place a bit for the holidays. We don't care to pry into our guests' religious beliefs and don't want to offend anyone, so just wondering if you'd enjoy some decorations?" If they say "We'd love Christmas decorations!" then you could even get a small tabletop tree and decorate it.
Just don't do what another host did that a guest reported here (I doubt you would, most hosts wouldn't)- the hosts went in the place when the guests were out for the day and decorated the place for Halloween to "surprise" them. The guests were really upset that the hosts had gone inside without prior notice.
