Does your translation need to be notarised?
Most documents need only a certified translation. Some need notarisation on top. A few need an apostille on top of that. Ordering the wrong level is the most expensive mistake available here, and it is entirely avoidable.
The three levels, briefly
Certified means a professional translation company attests, in a signed certificate of accuracy, that the translation is a true rendering of what was supplied. This is what most authorities in Singapore ask for.
Notarised means a notary public has attested the document with their seal on top of that. The notary is not checking the translation. They are providing a formal act that an overseas authority recognises.
Apostilled means a further stamp confirming the notary is genuine, for documents going to a country that accepts apostilles. Countries that do not accept them ask for consular legalisation instead.
Each is added to the one before. You cannot have an apostille without notarisation, and you cannot have either without the translation.
The rule of thumb
Staying in Singapore: a certified translation is usually enough. ICA and MOM accept them in ordinary cases.
Going overseas: expect notarisation, and check whether the destination country wants an apostille as well.
This is a rule of thumb and not a rule. Institutions set their own requirements and they differ more than people expect, including between two departments of the same organisation.
How to find out for certain
Ask the office receiving your document which of the three they need, and ask in writing. It is one email, and it is the only answer that counts. A translator cannot tell you, because it is not a translation question.
If they say "certified" without elaborating, ask whether they mean certified by a translation company or notarised by a notary public. Those words are used interchangeably by people who do not have to distinguish between them, and the difference is several weeks.
If it is the notary you need, not the translation
Sometimes the document is already in English and only the notarisation is missing. In that case there is nothing to translate, and what you are looking for is a notary public rather than a translation company.
Only the notarisation to sort out? What a notary public does, and what it costs .