Here you will find the details of the currently Linked merchant account to Google Ads. It will list the Account Id, status, whether it is active or not, and action, which means if the account is Linked or Unlinked. Refer to the page for better understanding:

Note: You can view/link only one AdWord account at a time, and to add another account in App, you need first to unlink the currently linked AdWord account and link the new one in App.