It's not something that we've researched in detail, but we have discussed before as a couple.
These are 2 related companies. I'm not recommending either as I've no experience of them, but it should give a pointer as to what options are available.
I suspect that talking to a funeral director would be a good place to start.
I told my children that when I die they should have the doctors remove any bits of me that might be of use to anyone else and then send the rest to a dog food factory. If they were feeling extravagant then have the bits that are left hurled into the sea using a trebuchet.
Once you are dead you are just meat.