I have a fire safe, actually a floor safe sunk in concrete. If you don't have one, you should get one for those important things, and even stuff that you can replace, but would be a pain, like your automobile certificate of ownership. If you rent, get a portable one, and if you can't trust your roommates, use a safe deposit box.

In my safe I have an envelope with "Bitcoin" written on it. Today, everybody knows what Bitcoin is, and when the safe is opened when you die, your heirs will find the Bitcoin envelope and the will hand it to whoever is the most techie.

In that envelope I have the backup words for the wallet on my phone, another with the backup words for the other wallet that I use for alt-coins, another with the backup words for my Trezor, and several paper wallets with various amounts of Bitcoin. If I haven't spent these when I die, my heirs should be able to extract them, and since it doesn't require paperwork, they can be quietly excluded from any inheritance tax.