The syntax to create dropdown lists in Survey123 is defined by the XLSForm specification. The syntax is well defined and strictly enforced. You will want to follow instructions as shown in this video tutorial. Our XLSForms Essentials help topic is also a good reference. In terms of importing lists into an XLSForm document, you can play all tricks you want in Microsoft Excel or the XLS editor of your choice, as long as you define your lists according to the XLSForm specification. For example, you can copy and paste values from other spreadsheets, you can import data from external sources, use formulas etc... All is fair game, again, as long as you follow the XLSForm rules for choice lists: They get stored in the choices worksheet and require at least three columns: list_name, name and label.
