SCS is a very helpful community so I'm sure you'll get some ideas here.
But if you have a little time, you can do some research yourself and pick and choose what ideas specifically are to your liking and meet your needs.
There are thousands of ideas on the internet if you do an internet search on 'easy Chrismas cards'.
Also, this search on YouTube returned 581,000 videos:
easy christmas cards - YouTube
NOTE: Some of the videos that the search returned do not appear to be easy Christmas cards, but you can bypass those.
Seniors are so forgotten in our society (I was a geriatric social worker at one point in my career) - this is wonderful that you're doing this - HAVE FUN !!!