I'm not sure if I've lost the option because of a role or permission change. It used to be here:
and also in the bulk edit options for Contact search results.
I've made sure that "Anyone can register" is checked in the WP sites general settings. I am using CiviCRM WordPress Member Sync and CiviCRM WordPress Profile Sync (Christian Wach ftw)
I've also made sure that the contacts have email addresses, and current memberships (if relevant).
What am I missing? It used to be here.