public class campaignClass {
    public static void campaignMethod(List<Lead>ld){
       
         String id='';
        for(Lead ls:ld){
            id=ls.Id;
           
        }
            system.debug('@@@@@ ld id'+id);
            
        Campaign camp=new Campaign();
        camp.Name='Monthly-Newsletter';
        insert camp;
        
        CampaignMember cm=new CampaignMember();
        cm.CampaignId=camp.Id;
        cm.LeadId=id;
        insert cm;
        }
    

}