Insert the texture means the URL

Hello i want insert the texture on plane means the URL. I use this script in C# but the system don't error returns:

 using UnityEngine;
 using System.Collections;
 using System.IO;
 
 public class OpenFilePanel : MonoBehaviour {
     
     
     
     bool modys = false;
     bool modus = false;
     private Rect windowRect = new Rect(Screen.width/2, 300,320,150);        
     string Text = "";
     string NameT = "";
     
     
     void OnMouseDown() {
 
         modys = !modys;
     }
     
     void OnGUI () {
     
         if(modys){
             // Register the window. Notice the 3rd parameter 
             windowRect = GUI.Window (0, windowRect, DoMyWindow, "My Window");
         
             }
     }
     
       // Make the contents of the window
    private void DoMyWindow (int id) {
     
              GUILayout.Label("URL:");
             
             Text = GUILayout.TextField(Text, GUILayout.Width(300) , GUILayout.Height(20));
         
             GUILayout.Label("NameTexture:");
             
             NameT = GUILayout.TextField(NameT, GUILayout.Width(300) , GUILayout.Height(20));    
             
             GUILayout.BeginHorizontal();
         
     
              if(GUILayout.Button ("Save")) {
                    
                    modus = !modus;
                     Save();
                     
                                     
                 }
         
                if(GUILayout.Button ("Close")) {
             
                    modys = false;
             
             
                }
         
         GUILayout.EndHorizontal();
        
             
             
     }
 
     
     // Update is called once per frame
     IEnumerator Save () {
         
         if(modus){
         
           string url = Text;
                     print(url);
                    // Create a texture in DXT1 format
                                 renderer.material.mainTexture = new Texture2D(4, 4, TextureFormat.DXT1, false);
                                 while (true) {
                                 // Start a download of the given URL
                                 var www = new WWW(url);
                                 
                                 yield return www;
                                 // assign the downloaded image to the main texture of the object
                                 www.LoadImageIntoTexture((Texture2D)renderer.material.mainTexture);
             }
         }
     
     }
     
     void Start()
 
     {
 
         StartCoroutine("WritePNG");
 
     }
 
     
         IEnumerator WritePNG()
 
     {
 
         // We should only read the screen buffer after rendering is complete
 
         yield return new WaitForEndOfFrame();
 
  
 
         // Create a texture the size of the screen, RGB24 format
 
         int width = Screen.width;
 
         int height = Screen.height;
 
         Texture2D tex = new Texture2D(width, height, TextureFormat.RGB24, false);
 
  
 
         // Read screen contents into the texture
 
         tex.ReadPixels(new Rect(0, 0, width, height), 0, 0, false);
 
         //tex.Apply(); //Needed? setPixels not called and it works without Apply.
 
  
 
         // Encode texture into PNG
 
         byte[] bytes = tex.EncodeToPNG();
 
         Destroy(tex);
 
  
 
         // Write to a file in the project folder
 
         File.WriteAllBytes(Application.dataPath + "/../" + NameT + ".png", bytes);
 
     }
     
     
     
     
 }

Recapitulating:

1- I want to submit a URL to take the picture. 2 - I want to be able to immediately place the texture on the floor. 3 - I want to save the texture.

Thank you for your attention. Help me.