In this guide · 8 sections
- 01UEN display rules by business type
- 02Companies Act section 144: what it actually covers
- 03GST registration number on tax invoices
- 04Website footer: best practice, not optional in spirit
- 05Email signatures, quotations and other documents
- 06Common mistakes
- 07Do it yourself or get help?
- 08Frequently asked questions
Short answer
Companies must show their name and UEN on letters, invoices, statements, notices and publications (Companies Act section 144). GST-registered businesses must show their GST registration number on tax invoices. Put the UEN in your website footer and email signature too.
UEN display rules by business type
The rules depend on the legal form of the business. ACRA's pages set them out for each type.
| Business type | What must be shown | On what |
|---|---|---|
| Company (Pte Ltd, Ltd) | Company name and registration number (UEN) | Business letters, statements of account, invoices, official notices, publications; name also on cheques, orders, receipts |
| Limited liability partnership (LLP) | LLP name, UEN and a statement that it is registered with limited liability | Invoices and official correspondence |
| Limited partnership (LP) | LP name and UEN | Invoices and official correspondence, such as receipts and letters to government bodies |
| GST-registered business (any type) | Supplier name, address and GST registration number | Every tax invoice and simplified tax invoice |
| Sole proprietorship or partnership | No equivalent rule found on ACRA's pages | Show UEN anyway as good practice |
Sources: ACRA's common offences page for companies, the LLP overview, the LP UEN page and section 144 of the Companies Act 1967. This is general information, not legal advice.
Companies Act section 144: what it actually covers
ACRA's summary of section 144 splits the rule in two. The company name must appear in legible letters on the company seal, business letters and statements, invoices and official notices, bills of exchange and promissory notes, cheques, orders and receipts, and letters of credit. The registration number must appear on business letters and statements, invoices and official notices, and publications.
IRAS has also reminded the public that section 144 exists so that people know they are dealing with an incorporated company, and that anyone can search a business entity for free. In practice, a quotation, invoice, receipt, statement or letter from your company should carry the full registered name (including "Pte. Ltd.") and the UEN.
GST registration number on tax invoices
IRAS's invoicing page/basics-of-gst/invoicing-price-display-and-record-keeping/invoicing-customers) lists what a tax invoice must contain:
- The words "Tax Invoice"
- Supplier's name and address, and GST registration number
- Invoice date and an identifying number
- Customer's name and address
- Description of goods or services
- GST rate, total excluding GST, total GST, and total including GST
For sales of S$1,000 or less including GST, a simplified tax invoice is allowed, which still needs the supplier's name, address and GST registration number. IRAS notes that for many businesses the GST registration number is the same as the UEN; if they differ (for example an M2-prefixed GST number), show both clearly labelled. Our GST tax invoice guide covers the full requirements.
Email signatures, quotations and other documents
Emails now do the work of business letters. Including the registered name and UEN in the email signature makes every message consistent with your letterhead and helps customers spot impersonators using a similar name.
Make one company-wide signature
Name, title, registered company name, UEN and website. Set it centrally in Microsoft 365 or Google Workspace so everyone uses the same version; our company-wide email signature guide explains how.
Update document templates
Quotations, invoices, receipts, statements of account, delivery orders and letterheads in your accounting software and Word or Docs templates.
Check payment instructions
Show the registered name as the account name for bank transfers and PayNow. A mismatch between invoice name and bank account name is a common fraud warning sign for customers.
Review after any change
If you change company name, convert to an LLP or register for GST, update every template and the website the same week. Converted LLPs must also show a conversion statement for 12 months, per ACRA.
Common mistakes
Most problems come from old templates, trading names and GST confusion.
Do
- Show the full registered name and UEN on every invoice and quotation
- Label numbers clearly ("UEN", "GST Reg. No.")
- Keep accounting software templates up to date
- Use the same name on invoices and bank account
Avoid
- Showing only a brand or trading name
- Printing a GST number before GST registration takes effect
- Charging GST when not GST-registered
- Leaving an old company name in email signatures after a change
Do it yourself or get help?
Updating a footer and an invoice template is a quick DIY job. Help is useful when you have templates spread across accounting software, e-commerce, quotation tools and email, or when a GST registration or name change means updating them all at once.
Our Business Website package (S$1,490) includes a compliant footer and legal pages. Xero / QuickBooks Integration (S$390) sets up invoice templates and connects your sales tools so every invoice carries the right details.
Frequently asked questions
Yes, if you are a company, LLP or limited partnership. Section 144 of the Companies Act requires a company's name and registration number on invoices, business letters, statements, official notices and publications. LLPs and LPs must show their name and UEN on invoices and official correspondence. GST-registered businesses must also show their GST number.
The Companies Act lists publications, but doesn't name websites specifically. Showing your registered name and UEN in the footer is still strongly recommended: it is your main public document, customers and platforms use it to verify you, and it costs nothing. If you sell online, include the same details in your terms.
Often, but not always. IRAS says many businesses have the same UEN and GST registration number, while others have a separate GST number, for example one starting with M2. If they differ, show the GST registration number on tax invoices and label both numbers clearly.
You can show your brand, but invoices must also carry the registered company name and UEN. Section 144 requires the company's name, meaning the registered name including Pte. Ltd. Using only a trading name can confuse customers and makes it harder for them to verify who they are paying.
We didn't find an ACRA requirement for sole proprietorships equivalent to the company, LLP and LP display rules. Showing your registered business name and UEN on invoices, your website and email is still good practice, and if you are GST-registered, the GST number must appear on tax invoices.