In certain situations, you may need to fill a drop-down list with elements from a spreadsheet.
To do this, simply use a specific merge field and enter it in the form field configuration.
Add the list of information to a column in your spreadsheet.
Add your dropdown option to your Clustdoc form and expand the field
Select the "Enter values" option
Enter the spreadsheet merged field as indicated in this article
This also applies to checkboxes and radio butons.