You are mixing a few things together. In Kentico, there are a few object types:
- User, your frontend website users will be here.
- Contact, the closest would be "a site visitor". Contact can be linked to one (or many) users, this linking is happening during the login process. If you try to log in with multiple user accounts within the same browser tab your contact will be linked to those multiple users.
- Persona. Only contacts can be assigned to personas, not users. The contact can only be assigned to one persona and only via persona scoring rules.
So, back to your question, the "user" cannot be assigned to the "persona", because there is no direct relation between them. It's Persona <1-to-1> Contact <1-to-many> User relation.
If you can explain in more details your case, what exactly (in business terms, not only technical) you need to achieve it will be easier to help you. Something like:
- I want all site visitors who log in with Azure Active Directory account to be recognized as "Azure AD Persona"
- Visitors logging in via other login providers should not be assigned to "Azure AD Persona"
- I want to personalize content for "Azure AD Persona", say, change the Hero banner
Is this your case or do you need to implement something different?