The Singapore Companies Act now requires every company to have the Company name and registration number on all business letters, statements of account, invoices, official notices and publications.
Suggested Readings
What happens if after incorporation I fail to maintain a registered office in accordance with the requirements of Companies Act?
What are the post-registration issues that I need to consider before I can start my foreign branch business activities?
How long does it take to incorporate a Singapore company?
Can I apply for an Employment Pass prior to incorporating my Singapore company? Why do I need to appoint a resident director?