Reply To: How do I set up usernames and passwords?

You could use the CSV Export Tool for Email found on the Connections : Tools admin page and then use a plugin like this one to import them as users. I’ve never used this plugin so I can not really vouch for it but it seems popular, well maintained and supported.

https://wordpress.org/support/plugin/import-users-from-csv-with-meta

But you will need the Link extension if the users are to be able to edit their entry.

Hope that helps!