Ho Santosh Reddy,

Custom Labels. Custom labels enable developers to create multilingual applications by automatically presenting information (for example, help text or error messages) in a user's native language. Custom labels are custom text values that can be accessed from Apex classes, Visualforce pages, or Lighting components.

Create and Edit Custom Labels:

1.From Setup, enter Custom Labels in the Quick Find box, then select Custom Labels.
2.To create a label, click New Custom Label. To edit a label, click Edit next to the custom label.
3.In the Short Description text box, enter an easily recognizable term to identify this custom label. This description is used in merge fields.
4.If you’re creating a custom label: In the Name text box, enter the name the label uses. This value is used in Apex and Visualforce pages to reference the custom label. Names must contain only alphanumeric characters, start with a letter, contain no spaces or double underscores, and be unique from all other labels in your org.
5.To mark the custom label as protected, check Protected Component.
6.For Categories, enter text to categorize the label. This field can be used in filter criteria when creating custom label list views. Separate each category with a comma. The total number of characters allowed in the Categories text box is 255.
7.In the Value text box, enter text up to 1,000 characters. This value can be translated into any language that Salesforce supports.
8.Click Save.

Please find the sample example below.

• http://www.infallibletechie.com/2012/11/how-to-use-custom-labels-in-visualforce.html

The advantage of using custom label is that label will be displayed to user depending on their language automatically. We need to specify translation for label using translation workbench.

After creating custom label we can use following code to use custom label in apex code.1 <!-- VISUALFORCE PAGE.

<!-- VISUALFORCE PAGE -->
<apex:page controller="CustomLabelApexDemoController">
   <apex:form >
     <apex:pageblock >
       Value stored in custom label is: <b>{!customLabelValue}</b>
     </apex:pageblock>
   </apex:form>
</apex:page>

// Controller class
public class CustomLabelApexDemoController {
    public string customLabelValue{get;set;}
    public CustomLabelApexDemoController(){
        customLabelValue = System.Label.DemoLabel;
    }
}

For further reference please check 

• http://www.iterativelogic.com/salesforce-custom-labels/

Hope it helps you!

Please mark this as solved if my reply was helpful so that it gets removed from the unanswered queue which results in helping others who are encountering a similar issue.

Thanks,
Nagendra