Hello Reggie,
Thank you for contacting the support. The list of valid call-to-action text are same as the one listed in the shared guide. If you are looking for these options via UI, please refer to the step 10.g in this article. For your other concern, the 'Automated' value is the default call-to-action text in UI which means google will select the call to action for you to show in the layout. Please click on the help icon right next to the field in the UI for more detailed information. Let us know if you have any additional concerns.
Regards,
Nikisha Patel, Google Ads API Team