There are a few different places to turn this off. To turn two of them off:
- First log into the tenant, and browse here: aad.portal.azure.com
- Then click on “Azure Active Directory” on the left pane.
- Click on “Password reset” on the middle pane (might need to scroll down). The Properties of “Password reset” will be visible. In the right pane, choose None, and click Save.
- With “Password reset” still visible, click “Registration” in the middle pane.
- Under “Require users to register when signing in?”, choose No, and click Save.
There are a few others, and there may well be more in the future.