Digital assets generally include electronic communications, images, videos, electronic records, reports and statements. This may mean funds in a PayPal account, funds or refunds in a Amazon or Etsy account, airline miles, photos, email, social media accounts.
First, you must distinguish what you own, such as funds in an account, some airline miles, as opposed to a service that you had a license to use, such as email and social media.
Digitals assets that you own and that are transferable by law will become part of your estate for your executor to transfer as they deem appropriate.
If you wish to preserve the data in your email or social media accounts for sentimental purposes, it is best to continually download that data while you're alive and store it in a safe place. Once you've died, it's unlikely that your executor can access your accounts unless the executor knows your login and password.
Some services may allow users to plan for their death. For instance, Google allows users to setup an Inactive Account Manager. Please check with your service providers.
Legislation is still catching up in this area so this will be updated accordingly.