Hi Uttpal,

Greetings to you!

You need to use <apex:form> tag. It is a section of a Visualforce page that allows users to enter input and then submit it with an <apex:commandButton> or <apex:commandLink>.

Also, I suggest to use <apex:pageMessages> tag. This component displays all messages that were generated for all components on the current page, presented using the Salesforce styling. And use try-catch in the controller. Apex uses try, catch and finally statements to handle exceptions.

Change your code as below.

Visualforce:

<apex:page lightningStylesheets="true" controller="EmployeeController" showHeader="false" standardStylesheets="false">
    
    <apex:form>
        <apex:pageMessages/>
        <apex:pageBlock >    
            <apex:pageBlockSection columns="2">
                <apex:inputField value="{!abc.Name}"/> 
                <apex:inputField value="{!abc.Custom_Code__c}"/>      
            </apex:pageBlockSection>
            
            <apex:pageBlockSection title="Work Address">
                <apex:inputField value="{!abc.Work_Address__c }"/>
                <apex:inputField value="{!abc.Work_Address_Line_2__c }"/>
                <apex:inputField value="{!abc.Work_City__c }"/>
                
                
                
            </apex:pageBlockSection>
            <apex:pageBlockButtons location="bottom">
                <apex:commandButton value="Save" action="{!save}" styleClass="slds-button slds-button_brand"/>
            </apex:pageBlockButtons>
        </apex:pageBlock>
    </apex:form>
</apex:page>

Controller:

public class EmployeeController {
    
    public Employee__c abc {get;set;}
    
    public EmployeeController() {     
        abc = new Employee__c();
    }
    
    public PageReference save(){
        try{
        	INSERT abc;
        }
        catch (exception e){
            
        }
        return null;
    }
}

I hope it helps you.

Kindly let me know if it helps you and close your query by marking it as solved so that it can help others in the future. It will help to keep this community clean.

Thanks and Regards,
Khan Anas