Hi,
On the AdWords API perspective, you can use the
ManagedCustomerService.mutateLink method to invite client accounts. Then, the client accounts or other manager accounts will be able to accept or decline the invitation either via
API or
via web interface. You may refer to this
guide to read more about linking account to manager account. Please also note that only the invitees will be able to accept or decline the invitation.
Please let me know if you have further questions/clarifications.
Regards,
Ejay
Google Ads API Team

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