You have number of options available when exporting Symbol as asset. You can choose to export with combination of different attributes of the Symbol.
You can export Bones with or without motion and object, if the Symbol has an armature layer.
You can export Object with or without Audio, if it is a not-rigged Symbol.
Motion and Audio can't be selected independently.
Depending on the options you select, Type field shows section of the Asset Panel where Asset would be placed. Also note that exported assets are saved in the Custom tab.
You can also specify comma-separated tag names, which are used during search operation.
If you have selected Export Asset, click Export to open the File Save dialog box. If you have selected Save As Asset, then exported asset is added to the Custom tab.