Hi @Rami ALZEBAK​,

As @Geeta mentioned, you can use the DESCRIBE HISTORY command to see the history of the table, but you can also look at the underlying data to see the .json files generated when committing changes to the data, This documentation is really good for understanding the history and versioning for Delta tables https://github.com/delta-io/delta/blob/master/PROTOCOL.md#delta-table-specification.

In terms of performance and cost, maintaining many versions of a delta table can affect performance and cost (although fairly minimal) so that's why you can use the VACUUM command to remove old versions and reduce costs & latency. This blog is good for going into more detail: https://mungingdata.com/delta-lake/vacuum-command/.