Hi Zahid,
Thanks for reaching out. Your client could use Adwords API to query the Campaign reports or others to retrieve the data they need. In order to fetch data from the API you have to set up the Developer Token, OAuth2 authentication and install the Adwords Client Library with your preferred language. Please follow the steps in this guide to finish the process and start calling the API and retrieving the Campaign data. Please let me know if you have any further concerns.
Thanks and regards,
Xiaoming, Google Ads API Team