How to delete Gmail account permanently?

Facing an issue with multiple gmail accounts? Interested in deleting an account permanently? No worries, on this ask Expert page you can find advice for all your queries.

If we have two Gmail account, one for official and other personal. How to delete one account so that the personal data is also erased permanently?

How to check the size of data to be moved to another account before closing it permanently.
What will the repercussions, if we close a Gmail account which is not given in any official documents?

Provide a detailed analysis report on this scenario.