You will need to use your Singpass to log in to OurSG Grants portal.
If you are applying for grants as an organisation, your organisation's Corppass Administrator will have to create a Corppass account for you and assign you the appropriate OurSG Grants portal role(s), so that you can access the OurSG Grants portal.
If your organisation does not have a Corppass administrator, find out how to appoint one here. The Digital Service Name for this portal is "Grant application via OurSg Grants portal".