Do I need to send diplomas with my application?Enclose copies of your diplomas only if stated in the job advertisement. Take original diplomas to the interview, as the employer may want to scrutinise them.
Should I supply references, letters of recommendation or proof of good conduct?You should mention in your application or your CV the names of a couple of referees the employer can contact. Make sure in advance that these referees are willing to recommend you, as references are usually requested. Some employers ask the applicants to enclose copies of any letters of recommendation in the application. Bring these to the interview, as many employers are interested in studying them closely.
It is usually mentioned in the advertisement if you need to prove that you have no criminal record. Only successful candidates will need to do this.