My employees want to contribute to their HSAs but want to make sure they get a tax benefit out of doing so. How does that work?

Employee contributions can be made to HSAs on either after-tax or pre-tax basis. If made on an after-tax basis they should be counted as an above-the-line deduction on their tax return, effectively making their
contributions tax-free. If they want to make the contribution pre-tax it can be done through a Section 125 (also called a “salary reduction” or “cafeteria plan”).