Mausoleum is the word you’re looking for. As I said above, you can buy a cemetery plot anywhere and place a marker. You don’t have to body to bury. You can bury ashes, you can place a marker.
This has come up a few times in my own family. One instance, the husband of an aunt was estranged from the rest of the family and he did not tell us where he placed her. We bought a marker for her anyway, in the family plot.
Another, a man was widowed twice, decades apart, and both wives were buried in different places. Arrangements had been made at the death of the first to bury him with her, so he was buried with his first wife. He was also given a headstone next to my mom, his second wife.
That’s the term; Mausoleum. I used to hear it a lot in Vincent Price movies, but never knew exactly what it meant. This is one of those conversations I cannot have with my adult siblings. It’s just a matter of time before my dad goes. Nobody wants to talk about ‘necessary arrangements’ now but me, so I let it drop, before I leave the wrong impression. Many folks are still rather superstitious about the inevitability or eventuality of death, not choosing to address the topic directly. I don’t have to make them uncomfortable about it, not now anyway.
If you are a veteran or the spouse of a veteran you are entitled to a free grave. My parents grave in a veterans cemetery overlooks the Pacific. They are surrounded by heroes. There is a lot more space available for cremated remains. The reason that I mention this is because I had a cousin who was a veteran. When he died his widow did not know that. I did not say anything because it was not my place to butt in.