rigidbody un freeze position via script code example

Example 1: rigidbody2d freeze position

public Rigidbody2D rb;

void Start()
{
	rb.constraints = RigidbodyConstraints2D.FreezeAll;
}

Example 2: rigidbody freeze position through code

rigidbody.constraints = RigidbodyConstraints.FreezeRotationX | RigidbodyConstraints.FreezeRotationZ;