To sell internationally you need to show this in your Site Preferences on your homepage here:
https://www.ebay.co.uk/ship/prf
On the left sidebar select Postage Preferences, scroll down to Exclude Postage locations and select the countries there you do and do not wish to post to. There is a little box at the bottom of that list to add this to any item listed , with no bids.
Be aware, if you are a new seller, or one returning after a long break, you may not be able to sell internationally straight away.
@blesso