option_id for multiple option custom field
i have a customized field with multiple options. the field is updated automatically with an Integromat automation based on an external mailing system(landing page). I want to make sure the automation does not erase past data in this field, and instead- updates it. I need the option_id of the various options in the field for this, also- how do I get the option_id for future options? since I will be adding more options all the time. thanks!