Mobile device screen sizes

Can I develop for the standard iPhone/Mini/iPad screen sizes at once? Or do I need to make some change and build for each one separately?

Is it just a matter of aspect ratio or is there more I need to know?

I think following code snippet work for you. Because it satisfy my needs nicely.
You have to attach this script to your camera object.

public class ControllingCameraAspectScript : MonoBehaviour
{
 
    // Use this for initialization
    void Start()
    {
        // set the desired aspect ratio (the values in this example are
        // hard-coded for 16:9, but you could make them into public
        // variables instead so you can set them at design time)
        float targetaspect = 16.0f / 9.0f;
 
        // determine the game window's current aspect ratio
        float windowaspect = (float)Screen.width / (float)Screen.height;
 
        // current viewport height should be scaled by this amount
        float scaleheight = windowaspect / targetaspect;
 
        // obtain camera component so we can modify its viewport
        Camera camera = GetComponent<Camera>();
 
        // if scaled height is less than current height, add letterbox
        if (scaleheight < 1.0f)
        {
            Rect rect = camera.rect;
 
            rect.width = 1.0f;
            rect.height = scaleheight;
            rect.x = 0;
            rect.y = (1.0f - scaleheight) / 2.0f;
 
            camera.rect = rect;
        }
        else // add pillarbox
        {
            float scalewidth = 1.0f / scaleheight;
 
            Rect rect = camera.rect;
 
            rect.width = scalewidth;
            rect.height = 1.0f;
            rect.x = (1.0f - scalewidth) / 2.0f;
            rect.y = 0;
 
            camera.rect = rect;
        }
    }
 
}

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

public class ControllingCameraAspectScript : MonoBehaviour  {
	
	
	// Use this for initialization
	void Start()
	{
		// set the desired aspect ratio (the values in this example are
		// hard-coded for 16:9, but you could make them into public
		// variables instead so you can set them at design time)
		float targetaspect = 16.0f / 9.0f;
		
		// determine the game window's current aspect ratio
		float windowaspect = (float)Screen.width / (float)Screen.height;
		
		// current viewport height should be scaled by this amount
		float scaleheight = windowaspect / targetaspect;
		
		// obtain camera component so we can modify its viewport
		Camera camera = GetComponent<Camera>();
		
		// if scaled height is less than current height, add letterbox
		if (scaleheight < 1.0f)
		{
			Rect rect = camera.rect;
			
			rect.width = 1.0f;
			rect.height = scaleheight;
			rect.x = 0;
			rect.y = (1.0f - scaleheight) / 2.0f;
			
			camera.rect = rect;
		}
		else // add pillarbox
		{
			float scalewidth = 1.0f / scaleheight;
			
			Rect rect = camera.rect;
			
			rect.width = scalewidth;
			rect.height = 1.0f;
			rect.x = (1.0f - scalewidth) / 2.0f;
			rect.y = 0;
			
			camera.rect = rect;
		}
	}
	
}

Hi.
The best solution for me is to use the theorem of intersecting lines so that there is neither
a cut off on the sides nor a distortion auf the game view.
That means that you have to step back or forward in dependency of the different aspect ratio.

If you like, I have an asset on the unity asset store which automatically
corrects the camera distance so you never have a distortion or a cut off no
matter which handheld device you are using. it is available here:

can someone update the code?

Hello plzzz help me i used this code but it never works on camera
i add this script in my main camera …
Answer me plzzzzz…
@ siddharth3322
is this script need to add only for one camera or every
camera in different scenes ???