Your SquareOffs account will operate independently of your Wordpress site, meaning you could use different SquareOffs accounts for different Wordpress sites. Or you could use the same SquareOffs account on different Wordpress sites, but the questions will all show as being "Asked by" the same user if you use the same SquareOffs account. 

Your SquareOffs account won't be "assigned" to any certain Wordpress/website. It is only connected by the SquareOffs login with which you choose to authenticate.