Unity script component to show debug text on your GameObjects when you need to see it in Game view, not just Scene view.

DebugTextGameView.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;


/// <summary>DebugTextGameView class
/// AUTHOR: Beard or Die
/// DATE: 2018-01-12
/// REQUIREMENTS: Add this script onto a GameObject that you want some debug text to 
/// appear over in Game View. Set up in inspector. You will also need to create 
/// an empty GameObject, add a TextMesh component, and drag that GameObject into
/// Project folder to create a prefab from it. Use that prefab in this script's
/// inspector for "Debug Text Prefab". This will allow you to change the style/size
/// of your debug text just once, rather than having to set that for every usage.
/// INSTRUCTIONS: If you want to specify custom text, choose Override style and 
/// call the public OverrideText method. Or choose GameObjectToString and override that.
/// Example: public override string ToString(){ return "Some custom string"; }
/// WARNING: This is for debug purposes, not for production. It's too ugly to use 
/// for real game usage.
/// LICENSE: CC0; change and use this however you like
/// </summary>
public class DebugTextGameView : MonoBehaviour {
	
	private bool isDrawn = false;
	private string overrideText = "OverrideText method not yet called. See instructions.";
	private Transform txtMeshTransform;
	private GameObject txtMeshObject;
	private TextMesh txtMesh;
	private float destroyTime;

	// INSPECTOR SETTINGS
	[Tooltip("If true, set visibleOnlyWhileKeyHeld to false")] [SerializeField] private bool isVisibleOnAwake = true;
	[Tooltip("If true, specify heldKey and set isVisibleOnAwake to false")] [SerializeField] private bool visibleOnlyWhileKeyHeld = false;
	
	[SerializeField] private Transform debugTextPrefab; // this prefab requires a TextMesh component attached on a child gameobject
	[SerializeField] private Vector3 textOffset = Vector3.up;
	[SerializeField] private Color color = Color.green;
	[Tooltip("In seconds; If 0, never auto-destroy")] [SerializeField] private float autoDestroyTime = 0f;
	
	
	[Tooltip("If visibleOnlyWhileKeyHeld is true, set this key")] [SerializeField] private KeyCode heldKey = KeyCode.LeftShift;
	
	[HideInInspector] public enum DebugDataTypes {TransformPosition, GameObjectName, GameObjectToString, Override}
	[Tooltip("Choose type of data to show")] [SerializeField] private DebugDataTypes useData = DebugDataTypes.TransformPosition;
	
	
	// PRIVATE METHODS
	private void Awake()
	{
		Setup();
	}
	
	
	private void Setup()
	{
		if(txtMeshObject==null)
		{
			isDrawn=false;
		}
		
		if(!isDrawn && txtMeshTransform==null)
		{
			isDrawn=true;
			txtMeshTransform = (Transform)Instantiate(debugTextPrefab);
			txtMeshTransform.position = Vector3.zero; // reset the prefab's position
			txtMeshObject = txtMeshTransform.gameObject;
			if(!isVisibleOnAwake) txtMeshObject.SetActive(false);
			txtMesh = txtMeshTransform.GetComponentInChildren<TextMesh>();
			
			txtMesh.color = color;
			
			if(autoDestroyTime>0)
			{
				destroyTime = Time.time + autoDestroyTime;
				StartCoroutine(AutoDestroy());
			}
			
			
		}
		
		if(isDrawn)
		{
			SetPosition();
			UpdateDebugText();	
		}
	}
	
	private void SetPosition()
	{
		txtMeshTransform.position = gameObject.transform.position + textOffset;
	}
	
	private void UpdateDebugText()
	{
		
		if(txtMesh==null || txtMeshObject==null)
		{	
			return; // prevent null reference exceptions
		}
		
		SetPosition();
		
		// Set text for debugging
		switch (useData){
		case DebugDataTypes.GameObjectName:
			txtMesh.text = gameObject.name;
			break;
		case DebugDataTypes.GameObjectToString:
			txtMesh.text = gameObject.ToString();
			break;
		case DebugDataTypes.TransformPosition:
			txtMesh.text = gameObject.transform.position.ToString();
			break;
		case DebugDataTypes.Override:
			if(overrideText!=null)
			{
				txtMesh.text = overrideText;
			} else 
			{
				txtMesh.text = "OverrideText not yet called. See instructions."; // to prevent this, see instructions
			}
			break;
		default:
			txtMesh.text = gameObject.ToString();
			break;
		}
		
		if(visibleOnlyWhileKeyHeld)
		{
			if(Input.GetKey(heldKey))
			{
				SetPosition();
				txtMeshObject.SetActive(true);
			} else {
				txtMeshObject.SetActive(false);
			}
		}
		
		
		if(txtMeshObject==null)
		{
			isDrawn=false;
		}
	}
	
	private void Update()
	{
		UpdateDebugText();
	}
	
	private IEnumerator AutoDestroy()
	{
		if(Time.time >= destroyTime)
		{
			Hide();
			Destroy(txtMeshObject,5f);
			yield break;
			
		} else {
			yield return new WaitForSeconds(0.1f);
			StartCoroutine(AutoDestroy()); // recursion
		}
	}
	
	
	// PUBLIC METHODS
	public void OverrideText(string newText)
	{
		overrideText = newText;
	}
	
	public void Show()
	{
		if(txtMeshObject!=null) txtMeshObject.SetActive(true);
	}
	
	public void Hide()
	{
		if(txtMeshObject!=null) txtMeshObject.SetActive(false);
	}
	
}

Result: