Whether you need a visa to enter Singapore depends on your nationality. Some nationalities can enter Singapore for short-term stays (typically for tourism, transit, or business meetings) without a visa. Others need to apply for a visa before traveling to Singapore.
The nationals of many countries, including the United States, Canada, Australia, the United Kingdom, and most EU countries, are allowed to enter Singapore for short stays without a visa.
However, visa policies can change, so it is essential that you check the current requirements with the Singaporean embassy or consulate in your home country or the official website of the Immigration and Checkpoints Authority (ICA) of Singapore.