If you wish you delete your account at a multi-user pod provider that runs the node-solid-server software (like currently https://solid.community and https://inrupt.net), you can do that as follows:
Step 1 is to go to your pod with your web browser. In this example, the pod provider is https://solid.community and the username is 'demo-account-deletion'. So in that case you would go to https://demo-account-deletion.solid.community/.
Make sure you include your username as a subdomain there, so not just https://solid.community/ which would be the pod provider's main page, not your account / pod. Fill in your own identity provider URL and insert your own username in there, just after the 'https://' part of the URL.
When you click 'Log in', it will ask you (in a pop-up window) which identity provider to log in with; choose your own pod, in this example 'demo-account-deletion.solid.community'.
And fill in your username and password to log in:
The pop-up will close, and you will be logged in:
Click 'Preferences', which should take you to:
Fill in your account name and click 'Send Delete Account link'. Note that as a security measure, this requires you (still) have access to the email
address with which the account was created.
When you click the link from the email, you should see this screen: