With a Streamline HR HSA, any earnings on your contributions are not subject to taxation. The HSA account is funded by pre-tax contributions by the employee.
Employers and other third parties can also contribute to the account. The employee determines the amount of money that is withheld each paycheck before payroll taxes are deducted. This gives employees more take-home pay, while you, their employer, pay less in FICA and FUTA payroll taxes.