Hi Priyanka,

You can write Apex trigger on case object, that trigger will call an Apex class, which will then create an 'Incident' in ServiceNow. Something like the code given below.

trigger CreateIncidentInServiceNow on Case (after insert) {
  for(Case c : Trigger.New){                                                  
  ServiceNowPostRequest.servicenowPostMethod(c.id);                                                                          
  }
}

public class ServiceNowPostRequest{
    
       @future(callout=true)
        public static void servicenowPostMethod(string incidentCase){  
        
        Http http = new Http();
        HttpRequest req =  new HttpRequest();
        HttpResponse res = new HttpResponse();
        
        String username = 'xxxxx';
        String password = 'xxxxxxxxxxxxx';
        
        Blob headerValue = Blob.valueOf(username + ':' + password);
        String authorizationHeader = 'BASIC ' +
        EncodingUtil.base64Encode(headerValue);
        req.setHeader('Authorization', authorizationHeader);
        
        req.setEndpoint('https://Your Instance/api/now/v1/table/incident');
        req.setMethod('POST');
        req.setHeader('Content-Type', 'application/json');
        
        JSONGenerator gen = JSON.createGenerator(true);
        gen.writeStartObject();
        
        Case c=[select Description from case where id=: incidentCase];
        gen.writeStringField('number', c.id);
        gen.writeStringField('caller_id','Alene Rabeck');
        gen.writeStringField('short_description', c.description);
        gen.writeEndObject();
        
        //you can now use String pretty as your body
        String jsonBody = gen.getAsString();
        
        req.setBody(jsonBody);
        res = http.send(req);
        
        system.debug(res.getBody());
        }
            

}

Mark Best Answer if this fulfills your requirement.