There are two broad routes, and the right one depends on whether the company is solvent and how clean its affairs are.
Striking off is the simpler and far more common route for a dormant or inactive company. You apply to ACRA through Bizfile, and the company must have ceased business, have no outstanding debts (including to IRAS and other agencies), no assets or liabilities, no ongoing legal proceedings, and be up to date with its filings. ACRA publishes the application and, if no objection is raised, strikes the company off the register after the statutory notice periods.
Winding up (liquidation) is the formal route where a liquidator is appointed to realise assets, settle creditors and distribute any surplus. It may be a members' voluntary winding up (where the company is solvent and the directors make a declaration of solvency), a creditors' voluntary winding up (where it is not), or a compulsory winding up ordered by the Court, for example on a creditor's application.
Whichever route you take, tax matters must be settled with IRAS – outstanding returns filed, tax paid, and GST deregistered if the company was registered. Apexia can advise which route fits, prepare the filings and handle the ACRA and IRAS steps.