The employer needs to apply for a work permit if they are hiring a migrant domestic worker in Singapore. The employer can apply for a Work Permit for an MDW either on their own or through an employment agency.
If you are in the very first time looking to hire a domestic helper in Singapore, then you will probably be looking for a maid agency Singapore which handles the complete maid hiring procedures. The important reasons why people engage a maid agency is

1. Applying work permit application & renewal for foreign domestic worker

2. Preparation for FDW's arrival

3. Getting the permit issued

4. Applying work permit cancellation & repatriation and etc...