Summary
Here are the steps to create a new Merchant Center account and convert it to a multi-client account (MCA), also known as an advanced account. You can only do this through the Merchant Center UI.
Manual steps
We recommend making a Google account that's unique to your business instead of using your personal account.
Because this account is for your business, you may want to consider its name carefully.
Sign in to the Google account you want to use for your Merchant Center account.
Create your Merchant Center account at the Merchant Center signup page.
If you plan to manage multiple Merchant Center accounts (one per merchant), request the conversion of your new Merchant Center account to an advanced account (MCA). See Convert to an advanced account for more information.
If other Google accounts need access to your Merchant Center account, set up user access.
Admin privileges are required for account-level changes, like modifying the users on an account or managing sub-accounts for MCAs.
Automatic steps
Not available for this process.