Your GMC account is the central hub for your product data. It needs to be linked to a verified Google Ads account to run Shopping campaigns. Since your GMC is already verified for your business, you'll simply grant the agency's Google Ads account permission to use it.
The Agency's Role: The agency will have its own Google Ads account, likely managed under a master "My Client Center" (MCC) account. This account will be properly verified to run ads in its country (e.g., the USA).
Linking Process:
You will go into your Google Merchant Center account.
Navigate to Settings (the wrench icon) > Linked accounts.
Find the "Google Ads" section and click on it.
You will enter the customer ID of the agency's Google Ads account.
The agency will then receive a request in their Google Ads account to link with your GMC. They will approve this request.
Once the accounts are linked, the agency's Google Ads account can access your product feed and start creating and managing Google Shopping campaigns for you.
Important Best Practices
While this is a great solution, you need to ensure you retain control and protect your business.
You Retain GMC Ownership: You must remain the owner and primary administrator of your GMC account. Your GMC is a vital business asset that holds your product data and domain verification.
Granting Access to GMC: You can grant the agency access to your GMC, but do so with caution.
Clear Contract: Before you start, have a clear contract with the agency that outlines:
Who owns the ad account and the data within it (they own the Google Ads account, but you own all the campaign data).
Who has access to what, and what happens if the partnership ends.
Payment and billing terms.
By following this approach, you can leverage a compliant, verified ad account without risking a permanent ban. It's the standard and safest way for international businesses to run Google Shopping ads.