Importing characters
To import custom soldiers from other sources, copy the provided bin file to the Importable character pool folder�the same place your character pools export to�and boot up XCOM 2. Head to the Character Pool from the main menu again, but this time, click on Import Character. Find the name of the bin file you�d like to import from and give it a click.

CREDIT: http://www.pcgamer.com/how-to-share-and-import-custom-xcom-2-soldiers/