Is this an actual paper envelope, or is it some sort of service on the internet? I feel like there must be a way to store encrypted files that, upon the presentation of a death certificate and a will, can be made available to the executor.

If I just leave a file or piece of paper with the passwords, I can see two problems easily. (1) Passwords change. (2) Some accounts may require multi-factor verification.

Like Chaos, I also came to the conclusion that leaving people things is not as good as leaving them memories or giving them things while we're all alive to enjoy said things.