Hi MIDHUN G REDDY,
Description:
The trigger should create a new record in a custom object called "Vehicles" when an Opportunity record is created with a specific value in one of its custom fields (the field is called "Type").  So, when an opp is created and saved with Type = "x", then the trigger should fire, and a new vehicle object record should be created that is populated with a few fields from that opportunity record.

Resolution:    
Here is a sample code for reference:

trigger createVehicleOnOpportunityX on Opportunity (after insert) {
    
    List <Vehicle__c> vehToInsert = new List <Vehicle__c> 
    // or whatever your custom object name put instead of Vehicle__c
    
    for (Opportunity o : Trigger.new) {
        
        
        // here is where you check if opportunity that is being inserted
        //meets the criteria
        if (o.Type__c = "X") {  
        
        Vehicle__c v = new Vehicle__c (); //instantiate the object to put values for future record
        
        // now map opportunity fields to new vehicle object that is being created with this opportunity
        
        v.SomeField__c = o.SomeField__c; // and so on so forth untill you map all the fields. 
        //you can also assign values
        v.anotherField__c = "test"; 
        
        //once done, you need to add this new object to the list that would be later inserted. 
        //don't worry about the details for now
        
        vehToInsert.add( v );
        
        
        }//end if
        
    }//end for o
    
    //once loop is done, you need to insert new records in SF
    // dml operations might cause an error, so you need to catch it with try/catch block.
    try {
        insert vehToInsert;    
    } catch (system.Dmlexception e) {
        system.debug ( e );
    }
    
}

To learn the basics of trigger refer to : https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_triggers.htm

Thanks.