Dear Dr Vandana Gupta The term “impact score” is meaningless and if called this way it is a wrongly used term. There are basically only two metrics related to impact:

CiteScore

Impact factor

For more info see for example https://uark.libguides.com/c.php?g=78889&p=6844222#:~:text=CiteScore%20calculation%20is%20based%20on,editorials%2C%20conference%20papers%2C%20etc. where they state: “CiteScore calculation is based on Scopus data, while Impact Factor is based on Web of Science data. CiteScore uses a 3-year window while Impact Factor adopts a 2-year window.”

Best regards.

PS. For more (misleading) metrics (often used by predatory journals) see: https://beallslist.net/misleading-metrics/