Andorra is part of Europe with capital at Andorra la Vella. Bhutanese citizens don't need visa for travelling to Andorra as tourist if they have Schengen Visa. The maximum duration of stay is 90 days. You can also find useful tips from fellow travellers.
Visa requirements for Bhutan
Andorra doesn’t require any visa, but entry/exit to Andorra is only through Spain or France which requires a Schengen Visa
Schengen visa must be multiple-entry or at least double-entry as the entry/exit to Andorra is only through the Schengen zone