Hi @AnjanChidige
1. When the user is added through above approach, can we see, which table in Dataverse, this entry is made?
Answer: They can't see the contacts table but the newly added users can access portal management. Evidence below

Note: Only the admin user or the site owner can assign an appropriate web role. Link provided in the previous reply
2. The record is created in Contact table, only when the user logged in into the site. This is not giving option for us to add the user to specific Web Role prior to the login. This mean, we need to wait until the user login to get the Contact record, then add to desired Web Role. But I would like to setup the users(Azure AD) with their Web Roles, before they login. Is this possible? Is there a way/Power Automate Flow available to perform this? Please suggest.
Answer: Our current method is assigning web roles automatically via power automate once the user is logged in to the site.
Adding reference here:
https://www.inogic.com/blog/2020/02/associate-disassociate-two-entities-with-1-n-and-n-n-relationship-using-relate-unrelate-records-in-power-automate/
Note: Currently, we allow users to select their desired web role and submit it for approval. Once the approver approved it then the power automate will trigger.
Hope this will give you high level idea of how to achieve your requirement. Have fun!
------------
If you like this post, give it a Thumbs up. Where it solved your request, Mark it as a Solution to enable other users to find it.