You can select every country you plan on visiting.
If there are multiple countries in the same continent, you can select the whole continent (e.g. ‘All of Europe’).
If you’re travelling to multiple continents or have an open-ended trip planned and don’t know exactly where you’ll end up, you can also select ‘Worldwide’.
If you’re only stopping in a country for 72 hours or less, you don’t need to add that country to your policy, as cover for destinations visited briefly (such as in transit) will be automatically covered.
For more detail, be sure to read the PDS.