SSFW is the Social Security Foreign Worker Number. From January 2019, all foreign employees iare required to be covered under SOCSO's Employment Injury Scheme and it will only have the employer contribution. In Swingvy setting, the contribution is set as SOCSO category second.
The employer is required to register the foreign employees through Perkeso Assist Portal. Then, Perkeso will generate the SSFW No for the employee. The SSFW No should be entered in the Payroll > People > Bank & Statutory information. Thus, it will be included in the SOCSO txt file that is downloadable in Swingvy.