You can just try this, which sounds like I’m being nasty, I’m not. Just go ahead and add a flat terrain and then a capsule and you can see where it is.
It’s positioned where the gameobject is so if you double click the object with the scene view selected it’ll zoom in on it.
Generally at it’s center but I wouldn’t get too hung up on where it is because…
Lets suppose you want to use a gun or a sword in your game and match that to the position of your characters hand, you wouldn’t use an offset of the characters transform.position you’d just add an empty game object in the players hand and an empty game object in the weapon where it should be held and then set them to be match up.
In other words a typical character can have multiple game objects for mount points so you could have separate transform.position and transform.rotation. e.g. a sword might be in the hand pointing upwards but a dagger may be in the hand pointing downwards, because you stab downwards (I’m told!).
So unless there’s some major thing you need to achieve I wouldn’t worry about it, it’s just a GameObject location and you can add other empty ones to fill your needs.