We will go through the code, let’s begin with controller code:

public with sharing class HPkeyprefix {    
    
    /**
      * Webkul Software.
      *
      * @category  Webkul
      * @author    Webkul
      * @copyright Copyright (c) 2010-2016 Webkul Software Private Limited (https://webkul.com)
      * @license   https://store.webkul.com/license.html
      */
    
    public String getprefix(){ 
         
        //Fetch all the URL parameters
        list<string> str = ApexPages.currentPage().getHeaders().get('referer').split('/');
        
        //Get the Key Prefix
        string kp = str[str.size() - 1].left(3);        
        if(kp=='o' || kp.contains('e'))
           kp = str[str.size() - 2].left(3);
        
        //Fetch the Schema of Your org    
        Map<String, Schema.SObjectType> gd = Schema.getGlobalDescribe();
        
        //Get the SObject
        for(Schema.SObjectType objectInstance : gd.values()){       
        
            if(objectInstance.getdescribe().getkeyprefix() == kp){
            
                kp = objectInstance.getDescribe().getName();
            
            }
        
        }
        
        return kp; 
    }
        
    
}

Now the visualforce page:

<apex:page controller="HPkeyprefix" showheader="false" standardstylesheets="false">

    <!--
    /**
      * Webkul Software.
      *
      * @category  Webkul
      * @author    Webkul
      * @copyright Copyright (c) 2010-2016 Webkul Software Private Limited (https://webkul.com)
      * @license   https://store.webkul.com/license.html
      */
    -->
    <apex:form >        
        <apex:outputtext value="{!prefix}"/>
    </apex:form>

</apex:page>

Step 1: Go to Setup > Customize > Home > Home Page Components. Click New.
Step 2: Write a suitable name for your component. Select the option Visualforce Area and click Next.

Step 3: Choose the Component Position as Narrow (Left) Column. Fill the related information and Save.

Step 4: Go to Setup > Customize > Home > Home Page Layouts. Edit DE Default.
Step 5: Check the home page component you just created. Click Next.
Step 6: Move your component to top and Save

That’s all about how to fetch SObject through key prefix in Salesforce, for any further queries feel free to contact us at:
https://wedgecommerce.com/contact-us/
Or let us know your views on how to make this code better, in comments section below.