Получите единство текстовых компонентов
GameObject.GetComponent<Text>().text = "Hello World!";
Comfortable Capybara
GameObject.GetComponent<Text>().text = "Hello World!";
numericalScore.GetComponent<UnityEngine.UI.Text>().text = "Score : " + scoreManager.score;
Text text = gameObj.GetComponentInChildren(typeof(Text)) as Text;
text.text = "text stuff";
text.font = prefferedFont;