They don’t understand the concept of Santa or Christmas as of yet. Our 7 yo is autistic but doesn’t say many words and only plays with specific things and our 5 yo may see him and know who he is but not what he does if that makes sense. In-laws are big on Christmas so they have experienced it but we don’t mention presents.
Before my husband and I married, we discussed Christmas and felt that Christmas was about spending time with family and friends, charity, not presents per se and we didn’t want future children thinking that that was what the season was about. Plus, if we ever fell on hard times, they wouldn’t have certain expectations.
I recall the many gifts that I received as a child and a teen (come from a massive family), forgetting about them and my mother talking about how much of it we never opened. I also remember that many of my best memories revolved around my family and the charity that I did, feeding the homeless, singing for the elderly, etc yet I could only name maybe a handful of presents that I loved.
When they are older and ask for gifts, we will likely get them within reason, but we don’t focus on Santa and presents. We have asked for family not to gift anything since the boys were content with what they have but that went down like a lead balloon so we just tell them a specific item that the boys are into and leave them to it.