Other companies may also be of help in planning your digital legacy. Many services offer online safe deposit boxes, for example, where you can stow away the passwords to e-mail accounts and other data. Accounts like this at SecureSafe, are free for up to 50 passwords, 10 megabytes of storage and one beneficiary, said Andreas Jacob, a co-founder. Accounts can be accessed from a browser, or from free iPhone, iPad and Android apps. The company also offers premium services for those who need a larger storage space, more passwords or more beneficiaries.

There is always your sock drawer or another physical repository to store a list of your user ID’s, should you be deterred from online lockboxes by fear of cyberattacks or the risk that computer servers that may not be there in a few decades, said Alexandra Gerson, a lawyer at Helsell Fetterman in Seattle.

“Make a private list of all your user names and passwords for all the accounts in which you have a digital presence, and make sure you update the list if you change login information” Ms. Gerson said. “Don’t put user names and passwords in your will, though, as it becomes a public record when you die.”

Make sure that your executor or personal representative understands the importance of preserving these digital assets, and knows how to find them, said Laura Hoexter, a lawyer at Helsell who also works on inheritance issues. “Preferably the person should be tech-savvy,” she said, and know about your online game accounts, your PayPal account, your online presence on photo storage sites, social media accounts and blogs, and even your online shopping accounts where your credit card information is stored so that the information can be deleted.

AFTER you die, an executor or agent can contact Facebook and other social media sites, establish his or her authority to administer the estate, and request the contents of the account.

“Most accounts won’t give you the user name and password, but they will release the contents of the account such as photographs and posts” to an executor, Ms. Hoexter said.

Transfer at death can depend on the company’s terms of service, copyright law and whether the file is encrypted in ways that limit the ability to freely copy and transfer it. Rights to digital contents bought on Google Play, for example, end upon the person’s death. “There is currently no way of assigning them to others after the user’s death,” Ms. Blagojevic said.