In my home country at least, the inheritance law follows the principle of universal succession. Definition vom Merriam-Webster: Succession under Roman or civil

In my home country at least, the inheritance law follows the principle of universal succession. Definition vom Merriam-Webster: Succession under Roman or civil law to the totality of a man's estate including both his rights and liabilities according to the principle that the heir is the same person as the deceased. With regard to accounts, it means that all your personal accounts become your heirs' accounts upon death. Enforceability in the US where most online servies are located these days remains an open question though … Personally, I have deposited my most important user credentials as print outs in sealed envelopes with two persons I trust. In addition, I have listed them in my will as executors for my digital estate. Working access to accounts is IMHO more important than ToS etc.