Why is my highscore not saving?

public class ScoreManager : MonoBehaviour
{
public Text scoreText;
public Text highscoreText;

public float scoreCount;
public float hiScoreCount;

public float pointsPerSecond;

public bool scoreIncreassing;

void Start()
{

}

void Update()
{
    if (scoreIncreassing)
    {
        scoreCount += pointsPerSecond * Time.deltaTime;
    }
    if (scoreCount > hiScoreCount)
    {
        hiScoreCount = scoreCount;
    }

    scoreText.text = "Score: " + Mathf.Round (scoreCount);
    highscoreText.text = "Highscore: " + Mathf.Round (hiScoreCount);
}

}

You haven’t initialised anything.

Or set scoreIncreassing to true or false anywhere. (it’s also spelt wrong; should be: scoreIncreasing)

public float scoreCount = 0.0f;
 public float hiScoreCount = 0.0f;
 public float pointsPerSecond = 1.0f; // change this
 public bool scoreIncreasing = true;
 void Start()
 {
 }
 void Update()
 {
     if (scoreIncreasing)
     {
         scoreCount += pointsPerSecond * Time.deltaTime;
     }
     if (scoreCount > hiScoreCount)
     {
         hiScoreCount = scoreCount;
     }
     scoreText.text = "Score: " + Mathf.Round (scoreCount);
     highscoreText.text = "Highscore: " + Mathf.Round (hiScoreCount);
 }