Please see Travel Advisories from the Singapore’s Ministry of Health (MOH) on COVID-19 :
From 26 Oct 2020, To apply for Reciprocal Green Lane (RGL) for short-term business and official travel between Singapore and Indonesia please refer : – https://safetravel.ica.gov.sg/indonesia/rgl/requirements-and-process
From 7 May 2021 2359 hours, The Stay Home Notice (SHN) will be lengthened to 21 days for travellers arriving from all countries and regions except Australia, Brunei, Mainland China, New Zealand, Taiwan , Hong Kong and Macau.
For more info: https://safetravel.ica.gov.sg/files/SHN-and-swab-summary.pdf