How to make a territory an enclave of another territory ?

Just make it as you would a separate country then make it part of whichever country you want.

Its a bit more complicated, if you really want an actual enclave? (territory completely surrounded by one country)

Then i suppose you would have to make it as you would make a lake (if you don't know how to check in custom map forums)... then create a country inside the "lake".

If you are just talking about an exclave then do as Xeno says.

Https://atwar-game.com/forum/topic.php?topic_id=10753

I found the answer. thanks anyways