All travellers will be required to download the TraceTogether app, or rent a TraceTogether token during their stay in Singapore.
TraceTogether for Visitors > https://safetravel.ica.gov.sg/faq#TT
How to set-up TraceTogether App > https://support.tracetogether.gov.sg/hc/en-sg/articles/1500002071841-I-m-travelling-to-Singapore-How-do-I-set-up-the-TraceTogether-App-