She's going to need it asap, so, just like I had to do with my MIL, someone's going to need to mention it.
We used a mausoleum, and they did order them for us, but in retrospect I wish that we had just gone to the registrar's office. I just like doing these things in a hands-on way.
I think we ordered 3 (AARP said something like 9 or more is what you needed!)...one or two had to be sent out then they were sent back, and we used the other for the places that accepted it being faxed to them.
I had everything so in hand, and the certificate was back so fast, that MIL didn't miss a single pension or SS payment, and all the accounts that needed to be closed, or have cards reissued in her name (Chevron, I think, was OK with just switching the name from his to hers), were done inside the month as well.