Google AdWords provides you with a unique ID, called a “GCLID,” for every click that comes to your website from an AdWords ad. By querying you’ll be able to see which keywords (Search String) are contributing not just to new lead submissions, but, more importantly, to actual sales.
How to Retrieve Keywords
You need to have an AdWords manager account to apply for access to the API. If you don’t already have a manager account, you will need to create one.
For Create new Manager Account follow the link.
Adwords API access:
For Adwords API access we need to submit the details, after logged in to your manager account:
Go to Gear Icon Account Settings- Adwords API Center.