To add a new dropdown option, follow the below steps:
Navigate to the Admin module, then click into the Control Panel where you create Custom Fields.
Find the Custom Field that you would like to add a new option to, then click the Pencil icon to edit that field.
From here, you are able to add an option by typing in the input field that says Add Option. Click Enter on your keyboard to add the option.
Once finished, click Save.
Note: This option will now appear wherever the Custom Field is used.
Please note: you must have Admin access to add a new dropdown option. If you do not have access to the Admin, please contact an Admin.