Vector3 stores X, Y and Z values.

Vector3 position = new Vector3(1f, 2f, 3f);

Useful values:

Vector3.zero
Vector3.one
Vector3.up
Vector3.forward

Distance:

float distance = Vector3.Distance(a, b);

Movement helpers:

Vector3.Lerp(...)
Vector3.MoveTowards(...)

Rotations use Quaternion:

Quaternion rotation = Quaternion.Euler(0f, 90f, 0f);