AIA (Application Initiated Action)

I am trying to modify the account management console and I see that AiA is recommended way to make certain modifications.
If I understand it correctly, AIA uses required user actions (in combination with oAuth2/OIDC flow).
Is it possible to create custom actions? For example, I managed to add some additional data to the dashboard by hitting the /userinfo endpoint, like group membership, user attributes, etc.

If I am going to change user attributes from the console, let’s say the address and phone number, can I do it via AIA or I would need to use admin REST API for that?