This command forms a union between the two specified countries.
form_union [country tag] [country tag]
|Country Tag||The tag of the country you wish to form a union.|
|Country Tag||The tag of the country you wish to form a union. If not specified, this will be the country you are currently playing as (so your current country would form a union with the first specified country).|
The above command would make your current country form a union with Brazil (country tag BRZ).
form_union ALB FIN
Albania's country tag is ALB. Finland's country tag is FIN. This command would make Albania and Finald form a union.